That One Boss/Action Game



Every action-packed spectacle needs some kind of conflict to up the ante. And when it comes to action games, there's no better way to do that than to add a boss or ten that will horribly beat the snot out of you.

Note: While Shoot'Em Ups are widely regarded as Action games, they have their own page. So do First-Person Shooters.

Batman Arkham Series

 * Compared to the other bosses in Batman: Arkham Asylum, Poison Ivy is a nasty brick wall. Hitting her when she's vulnerable is annoying enough since her fast-moving spore/pollen balls can easily hit you when you're aiming a Batarang. But in the fight's second phase, tons of enthralled henchmen will join the fight while she assaults you with constant waves of damaging vines. Because they linger for a while, the vines can cut you off from most of Ivy's tiny arena, and fighting hordes of aggressive enemies while dodging her attacks when you're boxed in like that is practically a Game Over waiting to happen.
 * The boss fights in Batman: Arkham City have a good reputation, and they've absolutely earned it. However, a certain trio of stealth-based fights will make you want to rip your hair out.
 * Normally, Mr. Freeze is a lot of fun. In fact, for most players he's Best Boss Ever material. But in a New Game+ run, he's a stress-inducing nightmare. First off, your attacks do a lot less damage to all opponents in New Game+, and Freeze is no exception. He's also a lot faster, his freeze ray is more powerful, and he'll jam your Detective Vision if you rely on it too much, which makes it harder to safely track him. Oh, and the fight won't end once you hit him with five or six different stealth takedowns: you have to hit him with almost every trick in Batman's playbook, meaning that the fight will come to a screeching halt if you don't know how to best utilize each gadget to attack Freeze.
 * Catwoman's already a lot harder to play as than Batman, but even if you find her fun in spite of her shortcomings, Two-Face will make you want to break your controller. He's backed up by a squadron of armed henchmen that he'll quickly replace if you take them out, and the second you start attacking him they'll all know exactly where you are and make a beeline for your location before pumping you full of lead. Catwoman's more fragile than Batman and doesn't have a smoke bomb she can use to confuse armed thugs, which makes it hard to escape before you're gunned down. Ultimately, beating Two-Face boils down to one of two strategies: either you slowly, methodically whittle down his health with hit-and-run tactics, or damage race him to victory while wildly tossing caltrops around and hoping they'll keep his men from firing at you. Neither option is fun.
 * Harley Quinn in the Harley's Revenge DLC is a lot like Two-Face minus the fight's one silver lining: the fight with Two-Face ends once you defeat the man in question. You have to beat Harley and her goons to win, and they'll take two different hostages during the course of the fight. If you get caught while trying to free a hostage, they die and you automatically lose.
 * As you'd expect from the man who broke the Bat, Bane is a menace in Batman: Arkham Origins. A lot of it boils down to his charge attack (elegantly dubbed "The Bane Train" by ), which is deceptively tricky to dodge and hits hard. He'll spam it with wild abandon during the showdown at Blackgate Penitentiary, and the thugs he has backing him up will gladly get in your way and make sure the big lug runs you over..
 * Most of Bane's fellow assassins are fun to fight, or are at the very least fair. Even Bane himself can be a blast for skilled players since his difficulty makes sense. Then there's Deadshot, whose boss fight is a nasty kick in the balls to a player expecting a good time. Like with Two-Face and Harley in Arkham City, he's a hellish Flunky Boss fought in a Predator Encounter, but unlike Two-Face and Harley, he's just as threatening as the gunmen he has backing him up. As befitting of his ultimate sniper credentials he can hit you from all sorts of crazy angles, and his body armor makes him immune to most of your attacks, save for the loud ones that will alert his goons to your presence. His love of screaming at his men and threatening to shoot them keeps them on their toes, and can lead to your cover being blown when they suddenly turn around, spot you, and try to gun you down. And right when you think you can breathe easier once you get him on his last legs, he'll take a hostage and will kill him if he or his men see you. It doesn't matter how well you've been doing so far: the hostage dies? You lose. Thank god he's optional... unless you're gunning for 100% Completion, and in that case you'll have to fight him sooner or later.
 * The titular Arkham Knight from Batman: Arkham Knight is hyped up as being Batman's ultimate opponent. And he delivers... perhaps a little too well, as two of his three fights can attest.
 * The Cloudburst tank he pilots during the first fight against him is backed up by several Cobra drones, which you have to defeat before you can even think about hurting it. They're annoying enemies with unpredictable movement patterns, ensuring that you'll be banged up at least a little bit before fighting the Cloudburst itself. The main tank in question isn't too bad at first, but each time you destroy a weak point it puts on a terrifying burst of speed and will aggressively chase you around Gotham City while firing off powerful laser blasts. If you haven't mastered the Batmobile's controls yet, this fight will force you to.
 * The second battle has the Arkham Knight chase you around a network of tunnels in a giant excavator. To hurt him, you have to bait him into chasing you down certain tunnels with explosives that will detonate once he passes them. The problem is, these tunnels are cramped and filled with obstacles, and if you run into so much as one of them, the Knight's excavator will catch up and instantly kill you. Even if you've mastered the Batmobile's controls by now, it's still incredibly nerve-wracking and frustrating to navigate those tiny little tunnels.

Castlevania

 * Castlevania features Death. The fight is significantly harder than the previous bosses as well as the final boss, you can only take four hits before you die (assuming you got through the ridiculously hard corridor without taking damage), and even after you kill him, his sickles remained active. Many a player has beaten Death only to die while trying to exit the stage because of those things. He is That One Boss so often in the series that fans tend to complain when he's not.
 * In Castlevania III: Dracula's Curse, Death returns with essentially the same attack pattern as he had in the first game. But players quickly discovered that the boss fight wasn't over even after you emptied his energy meter. Oh, no - he just comes back with a second energy meter as a giant ghoulish head that moved in a looping pattern that was very hard to dodge.
 * In Aria of Sorrow, he could summon vertical energy beams that chase you. If you're close to a corner you can't evade it. Once you knock him out of this phase, he'll pull out a Double Scythe and throw/dash around with it.
 * Death in Aria was tough mainly because of the double scythe. His three attacks with it all hit hard and are fast, and the fastest is also the hardest one to dodge.
 * In Dawn of Sorrow, it's not too bad until phase two. Now he can teleport right in front of you and spam sickles. The best attack is when he spams GIANT SKULLS FROM OFF SCREEN that take 80% of your life. If you're hit by one, you are likely to recoil into another one. Fun!
 * Even in Harmony of Dissonance which was pathetically easy, Death's second form could sometimes juggle you into a corner and shred you without a chance to heal.
 * In Portrait of Ruin, he summons these weird floating hands that grab onto you and hold you in place while he hacks you to bits. You're supposed to have the character who isn't trapped free the one who is, but the timing is really hard to pull off. Even better is that he switches his weaknesses at random between Light and Darkness.
 * In Order of Ecclesia... well, he lives up to the game. That damn black spiral (which can only be dodged, counter-intuitively, by getting close to him) is probably the worst part.
 * His Harmony of Despair incarnation might top all of the above. First off, the bastard turns invisible and moves outside of his quarters and actively attacks the other players with his flying scythes, which become nigh impossible to avoid in certain areas. The only way to stop him from doing this, which is not explained at all in-game, is to align the two spotlights on each side of the map to reveal him and move him back to his room, or to deal enough damage to him, which can be difficult due to all the other enemies you need to avoid at the same time.
 * Death from Rondo of Blood deserves mention too. To start with, the battle is annoyingly long, having three phases. In the first phase, Death uses his usual routine of spamming sickles all over the place that are hard to dodge, and he also likes to float up in the air out of your reach. In the second phase, he goes to the background, and shoots a wave of huge skulls into the foreground at you. What's worse, though, is that if you get hit by even one skull, Death will launch another wave. You have to dodge an entire wave in order to progress to the third phase. In the third phase, Death comes back to the foreground and stands on the ground to fight you. His attacks now are easier to dodge, but you're probably low on health by this point. Also, you can't throw crosses at him anymore, as he'll just block them and counter with a magic attack.
 * It's even worse in the SNES Dracula X. It's the same fight, but it takes place on the top of the clock tower rather than a ship. This gives you much less room to move around and dodge the sickles in his first form. What makes it worse is that Death himself couldn't hurt Richter in Ro B by touching him, but in Dracula X, he not only does damage, but curses Richter, making him move much slower. To add to that, his spinning attack in his second form must be dodged by leaping towards the edge of the clock tower as Death spirals toward you. Which means that 50% of the time, you'll overshoot your jump and fall off.
 * In Super Castlevania IV, Death doesn't really have any special tricks or anything aside from trying to suck you in which is arguably the easiest part to avoid and damage him with. It's just a nightmare literally because of the scythes and how quickly they come with bizarre orientations.
 * Castlevania also has Frankenstein's Monster. By himself, he was an irritatingly large target to avoid. The real issue here was Igor, an invincible Fleaman that shot fireballs. Dodging the huge monster, the unpredictably moving Igor, and the fireballs at once is notoriously difficult.
 * Castlevania 64 ramped up Frankenstein to ridiculous steroid addict levels by making him basically invincible and giving him a CHAINSAW. And, for good measure, Frankenstein is accompanied by two demonic dogs who 1) stun you so Frank can catch up and 2) run considerably faster than you. They're invincible too.
 * The two Zombie Dragons in Circle Of The Moon have caused many a restart, even if you've been leveling up your character.
 * Adramelech too, made all the more jarring by the fact that the previous three bosses were all complete wusses.
 * Symphony of the Night has The Doppelgangers, which can be quite tough if you don't know about the Red Rust trick.
 * Beelzebub can also put up a tough fight, especially when he's almost dead. He's just a head and part of a shoulder, near the ceiling, surrounded by giant flies. The axe makes it somewhat easier, but it still takes a while.
 * Castlevania: Portrait of Ruin has the vampire sisters Stella and Loretta. The vampires' attacks deal enormous damage, especially their ice sword technique, and you have to keep them off of Charlotte for about fifteen seconds so she can cast a particular spell. You only need to hit one of them with it, but there's very little you can do to ensure that they're in place when Charlotte completes it.
 * Aria has, aside from the already mentioned Death, "J". If you don't know about his resistance to holy damage, and you try to use your Infinity+1 Sword against him (or don't have a choice), he can easily be That One Boss.
 * And after the fight, Soma actually notes that he was holding back, to the point where your average vampire hunter is tougher than that. Makes you wonder how ungodly hard he'd be if he WASN'T holding back. He's also far faster than every other boss in the game and moves so erratically that you basically have to have to constantly use Black Panther to get away from him.
 * Gergoth from Dawn of Sorrow is a pain in the ass; he's huge (in a one-screen room), shoots a frickin laser beam that sweeps across most of the room, and the only "safe place" you can attack from is directly under his head, even though he walks back and forth and has a tendency to release poisonous and petrifying gases from that spot. And then he gets faster. To top it off, he does way more damage than previous bosses; if you haven't been power-leveling, he'll only need a few hits to kill you.
 * If you defeat Gergoth as he's using his laser attack, you'll probably get hit and die as his head moves up towards the ceiling.
 * Eligor, from Order of Ecclesia. One of the bosses in Dracula's Castle, Eligor is a giant metal centaur. He seems easy enough at first. At first.
 * Explanation: it's a Colossus Climb boss. Aside from using glyphs such as Redire to skip parts of the battle (which in itself is tough to get right), there are multiple phases to Eligor. Firstly, you must destroy these red knee blocks on the front and back of his legs while he's attacking you every so often. You have to climb underneath him to get to the back ones, and it's not that easy to do due to Collision Damage. He also has bows and arrows at the front and back, which, while destroyable, are tough to avoid (especially in Hard mode), and if you don't destroy them, they'll cause problems. Once you've finally destroyed his knee things, he'll buck down and you can climb up to his back, where you can hit his head, which is how you kill him. If you haven't destroyed the bows, you will get arrow spammed. Even if you have, he obviously tries to knock you off. The patterns of his attacks are VERY hard to predict and memorise, and he does a lot of damage to you at the best of times even before this. If you get knocked off (likely to start with, he attacks in awkward ways which often involve ducking and hoping you don't slide too far into him for Collision Damage), you'll have to take down the knee things at the back again, albeit with less health.
 * Speaking of Ecclesia, what about Blackmore? Admittedly, he's not as hard as Eligor but he's a real pain in the ass if you want the medal. Especially when he does that fire breathing combo of his, and it really doesn't help that you're more or less stuck in the corner for the entire fight. And he'll kill you in about 4 hits, tops.
 * Brachyura. Whereas Arthroverta was a pushover, and the Giant Skeleton was a pain, but still doable, with Brachyura, if you don't figure out how to dodge all of its attacks, you're dead. Doesn't help that he spends half the fight invincible.
 * Gravedorcus, the land shark boss in Oblivion Ridge. Not only does he spend half the fight underground, but that attack where he jumps out of the ground is a nightmare to dodge.
 * Then there's . He has a crapload of attacks, all of which are hard to dodge. His standard gunshot, which gives you no warning whatsoever, his flaming kick, which makes it very hard to jump over him, and his Vertical Shot, which is a pain to dodge, are probably the worst offenders. There's one saving grace though: he's the one of the two bosses you don't take damage from by touching him. So you can just run or slide by behind him to dodge all of his attacks.
 * In Castlevania: Curse of Darkness, every boss starting with the first encounter with Trevor "Asshole" Belmont is That One Boss. Trevor is the the third boss, by the way.
 * Especially Dullahan, what with his shockwave attack. And the boss before him? Trevor, again. And of course, he's even worse the second time.
 * Harmony of Despair has the boss of the downloadable Chapter 7. It's a replica of Astarte from Portrait of Ruin, and she has every attack it had back then, including the ability to Charm male characters, which is nigh impossible to avoid. And you can still be hurt by the boss while you're charmed. There's even an achievement for killing a charmed teammate! The only real way to avoid being charmed outside of precision-timed double jumps is to simply stay out of the battle if you aren't playing as Charlotte or Shanoa (they're immune to charm.), or beat the level solo with Charlotte. Or Shanoa.
 * Puppet Master, the 2nd stage boss. He sends out a series of exploding dolls, moves around the entire map, and creates puppets which he can place inside the iron maidens scattered around the map which he then proceeds to magically swap with yourself. And the iron maidens can kill you instantly. You CAN destroy the puppets, but chances are you need very good synchronization with your teammates in order to do so, they each take a set number of hits to destroy, and the more players there are, the more hits they take, maxing out somewhere around 30 with the maximum of 6 players. Good luck hitting the damn things enough times in the few seconds it takes him to place one inside an iron maiden without a team of Blender Somas.
 * The Iron Maidens only kill you instantly on Hard Mode. On normal they still do a crap load of damage. If you plan on playing online, chances are all the games you play will be on hard mode, woe be to you if you haven't grinded yourself in singleplayer.
 * Stage 10 has 8-bit Dracula, who fills the screen with ridiculously fast fireballs that can only be dodged with precision-timed jumps, and trying to avoid them by jumping over him just causes him to do an extremely fast backdash into a corner followed by the usual fireball spread. If you manage to beat him, he then naturally changes to his second form, which has an extremely quick dash attack that does colossal amounts of damage and a fireball spiral that takes yet some more precision jumping to avoid. If players try to hide outside the boss room, he counters by attacking with an even harder-to-dodge fireball spiral that goes through walls to boot.
 * Stage 11 has Ryukotsuki, the final boss of Getsu Fuuma Den who has 3 forms: the first one isn't particularly hard to kill, but you can easily get hit by his wild leaps if you don't stay grounded. The second one is slow, but he can block attacks high and low and throws poison daggers to wear you down for the third form, which can summon the 3 minibosses from the stage that you need to kill to be able to fight him, possesses a hard-to-reach weak point that's only vulnerable for a few seconds at a time and loves spamming fireballs that bounce all over the screen, split into smaller fireballs and petrify you upon hit.
 * Castlevania II: Belmont's Revenge has Soleil Belmont. He has a ton of health, his whip has the same range as yours and does a hell of a lot of damage, and he can throw homing swords which are difficult to dodge. Exploiting his AI is practically required to defeat him.
 * From the Lords of Shadow DLC Resurrection, we have The Forgotten One. Easily harder than any other boss in the game, and for mostly all the wrong reasons: see Lo S' YMMV entry for more details.
 * The Doppleganger from Castlevania III: Dracula's Curse. He's armed with your characters' most powerful special attacks and can take a quarter of your health whenever you get hit. Not helped by the fact that the level to get to the boss is just as annoying, so unless you've memorized the level quite well, you're more than likely to be battered and bruised by the time the fight starts.
 * The Werewolf from Castlevania Chronicles is easily one of the toughest bosses in the game, rivaling Death in terms of frustration. Reaching her with full life is a problem in and of itself, since her stage requires lots of memorization. She herself moves extremly quickly, and likes to hang onto places where the slow axe is the only weapon that can reach her. While she's bounding around like a maniac, she's also tearing off pieces of rock and the clock tower's numerals to throw at you. Though they can be destroyed by whipping them, most of the time the angle they're at makes it nigh impossible to react and whip them. Finally, at that point in the game, a mere 4 (5 on Arrange mode) hits will send Simon to the grave, meaning you have to fight your way to her again.

Crash Bandicoot

 * The first Crash Bandicoot game has N. Brio, who has the most health of any boss in the game, even Neo Cortex. He starts by throwing exploding chemical filled beakers at you which you have to dodge, and then hit the green remains back at him, then after he loses enough health he Turns Red and drinks a special potion which causes him to transform into a giant Hulk-like creature who tries to cause the roof to fall on top of you. The only way to damage him at this point is to dodge the falling debris, stand on top of it, and wait for him to charge at you so you can jump on top of his head (which is in no way obvious for a first-time player). You have to do this this several times before he finally goes down, and due to the difficulty of this fight, it almost puts Neo Cortex straight into Anticlimax Boss territory.
 * Ripper Roo is also pretty bad, because you can't hurt him unless you detonate a TNT Crate while he's right next to it. The only problem is that Ripper Roo is a total spaz who hops around the battlefield like he's on crack, and TNT Crates take a while to explode once you prime them (unless you attack them, but you'll get hurt by the ensuing explosion), making it infuriatingly difficult to get the timing down for hitting him. And as if that wasn't annoying enough, the fight takes place on a river. And unless it's an underwater level, falling into water in a Crash Bandicoot game is almost always instant death, this game included.
 * The second Crash Bandicoot game has N. Gin, who has a powerful spaceship you have to destroy by throwing Wumpa Fruit at it. It doesn't help that the ship takes a lot of punishment before it loses one part of its health bar, and all the while you have to avoid massive amounts of lasers, missiles, and other nasty projectiles while you're still trying to hit it. The best part is during the last phase of this battle, N. Gin will temporarily destroy one of the three platforms you can stand on, making this sequence much harder than it should be. Just like the last game, this fight pushes Neo Cortex into being Anticlimax Boss territory.
 * Ripper Roo returns in this game, but being downgraded to the game's Warmup Boss means that he's been completely defanged. So instead, he's got Tiny Tiger filling in for his "annoyingly mobile boss fought over a death pit" status. The "fight" is less of a fight and more of a chase where Tiny's constantly leaping after you over a series of platforms suspended high in the air. Several of the platforms will occasionally drop into the abyss, and you're supposed to trick Tiny into being on one of the falling platforms to hurt him. The problem is that doing so without plunging to your death is surprisingly hard to do, and you can even die after defeating Tiny if you aren't careful.
 * The third Crash Bandicoot game has N. Tropy who can use his time powers to shift the position of the platforms you're jumping on to reach him, as well as shoot electricity and other projectiles to prevent you from reaching him easily. He also has a good amount of health, speed, and intelligence, so beating him usually takes a few tries.
 * Also in that game N. Gin makes a return appearance with a new and improved spaceship which Coco Bandicoot must use her plane to destroy. It has the most health of any boss, once again sporting more than Neo Cortex, and will continue to Beam Spam, shoot missiles, and launch even more projectiles than his first ship in the second game. The best part about this fight is when you destroy the first ship, N. Gin escapes into a smaller ship which is even faster and fires more projectiles, and you have to beat both of these ships consecutively on one bar of health. Basically, if someone in the Crash Bandicoot series has N. Something as their name, you know they're going to be extremely tough. Unless it's Cortex, who's always a pushover.
 * Dingodile isn't much tougher than Tiny Tiger in the original game, but various tuneups to his fight in the N. Sane Trilogy make him a lot more dangerous. Dodging the jets of fire he shoots from his flamethrower used to be a non-issue, but now it's his deadliest attack thanks to annoyingly good tracking on his end. He'll even cancel out of his "aerial bombardment" early and immediately start trying to roast you, forcing you to dodge the jets of fire and the fireballs crashing down from above.
 * Despite being a Mario Party clone, Crash Bash has some surprisingly tough bosses. It speaks volumes about this game's difficulty when even Papu Papu can kick your ass if you're expecting a walk in the park.
 * Bearminator, the second boss, isn't quite as bad as the guys who follow, but he's definitely where the boss difficulty truly ramps up. His fight is a modified version of Polar Push where you have to knock his robot bear minions off a platform before shooting him with a missile. Not so hard on paper, but the stage is slippery, tilts, and every time he takes damage, Bearminator shoots it with a missile and breaks off a chunk so you have less room to move around. Once you've hit him twice, the stage is half as big as it once was and you now have three robot bears gunning for you. And remember: because this is technically Polar Push, getting knocked off the edge means you die.
 * Moe and Joe, the Komodo Bros. Their fight is a two-phase version of Tank Wars, and neither phase is easy. The first has you destroy their gigantic war machine's weapons while they shoot you with a barrage of projectiles that bounce around the tiny battlefield, and the second has them both come after you in tiny tanks. While the second phase is technically more manageable since there are less projectiles to worry about, the Komodo Bros make up for it with their aggression and love of ganging up on you. And you better hope they don't kill you during the second phase, because if they do? You have to do the whole fight all over again.
 * Nitrous Oxide (Yet another N. boss) may be the final boss, but that doesn't make him any less frustrating. Like with the Komodo Bros, his fight's split into two equally obnoxious phases. The first has you chase Oxide's spaceship through a dangerous obstacle course while dodging his attacks, which are incredibly quick homing missiles and trails of dangerous Nitro Crates respectively. Get past that, and you have a hellish game of Ballistix to look forward to. It's the air hockey equivalent to Bullet Hell, because you have to contend with a ton of pucks trying to slide into your goal all at the same time while Oxide tries to blast you with missiles and exploding balls. This fight's one saving grace is that unlike the Komodo Bros, dying on the second phase won't kick you back to the first, but it's still a grueling fight in spite of that silver lining.
 * Crash Bandicoot: The Wrath Of Cortex's second boss stage, Drain Damage. This is Crunch using the power of the water elemental mask, Wa-Wa. You'll lose many, many extra lives to this insanely hard hurdle puzzle - and to make it worse, it was only the second boss in the game.
 * To elaborate further, Drain Damage has FOUR STAGES. Each of these stages have you crossing some platforms suspended in the water that sink (thus killing you) if you stay on them for too long. In the first stage, Crunch fires blue lasers that you must jump over and spin-attack Crunch when you reach the end of the platforms. In the second stage, he continues using the blue lasers but also introduces green fire that you must duck or slide under. In the third stage, he introduces an attack where he pounds the ground with his fists, causing the platforms to shake which makes it easier for you to fall off. In the final stage, he uses all of his attacks in a rapid-fire movement. And remember that it's Crash Bandicoot, so one hit and you have to start all over. Good luck!
 * The fourth boss stage, Atmospheric Pressure, is infinitely worse, due to the fact that you are in the plane and most of Crunch's attacks are nearly impossible to dodge.
 * Don't forget the fact that the giant Crunch takes FOREVER to kill. You'll be constantly dodging his attacks and he'll still have three quarters of his health left.
 * In Crash of The Titans, Uka Uka is That One Boss. He fires volleys of shots at Crash, who is usually trying to fight (or run from) Ee-lectrics and Battlers. And, like every other Titan in the game, he heals stupid-quick. Good luck stunning him with one blow.

Dead Rising

 * As pictured above, the original Dead Rising game give us the three escaped convicts in the jeep with a mounted machine gun. Insanely fast in their jeep, with the machine gun for long-distance attacks and a bat for close-up damage if they don't decide to just run you over, they are easily the hardest boss in not just the game, but the series. And to add onto that, the first time you meet them you've got to rescue their target while helping at least one helpless woman at night, you'll be thrown into fits of rage any time you hear the opening lines of their battle song. And in the event that you do kill them, you can't even rest easy because for some ungodly reason, they respawn the next day.
 * Cletus Samson from the first game is brutal: his shotgun has a hell of a kick, and by the time you get back to your feet, he'll blast you down again. If you try to fire back with your own gun, he tends to be quicker to the draw unless you have great marksmanship skills. And if you try to hop the counter, he'll simply toss you back over. Given that his store has little cover, this is also one of the most frustrating bosses in the game.
 * Sean Keanen is also deceptively difficult. You'd expect him to at least be slow due to his old age, but nope, he's a spry old geezer who can easily keep up with you and slash you to ribbons. His sword also has a lot of range, and it hurts].] Oh, and did we mention that he's backed up by a legion of [[Demonic Spiders|True Eye cultists?
 * Among the story bosses, Isabela Keyes is easily the worst. Like the Convicts mentioned above, she rockets around in a vehicle, and unlike the convicts who could at least be hurt while moving, a bug makes her completely invincible whenever she's in motion, which is pretty much all the time. Even when you get her motorcycle to stop, it's very likely that she just won't take any damage anyway and will chip you away with gunshots. And if you leave the area for any reason, she'll disappear and the story stops dead in its tracks, forcing you to either start a new game yourself or take advantage of the remaining days to level up. Oh, and thanks to a developer oversight, the cutscene that plays when the zombies grow more aggressive at 7:00 PM also despawns her, meaning that she's not only an annoying boss, but an annoying boss with an unforgiving time limit.
 * Her brother Carlito is tough but manageable in his first and third fights, but he's just plain hard in his second. He has access to a powerful sniper rifle and will do heavy damage with every shot he lands. He's quick on the draw and rarely ever misses, so you're usually better off saying "screw this" to the sniper duel the game tries to nudge you towards, popping a Quickstep, and damage racing him to victory by beating the tar out of him before he can kill you.
 * Dead Rising 2 features boss battles just as infuriating as its predecessor. Really, take your pick. Most of them suck if your experience level isn't high enough. Among the worst:
 * Randy Tugman, an obese man in a gimp mask who can run incredibly fast, and has a giant, pink chainsaw with ridiculously oversized range of attack.
 * Antonie Thomas, who can block machine gun bullets with a frying pan. He's also a Cheating Bastard with some serious Hitbox Dissonance, can choke Chuck with an apple (an attack that deals surprisingly high damage), and periodically heals himself (this is actually his weakness, so slash him with the knife gloves while he's eating!). The only saving grace is that he's quite slow, so you can just run around until he decides to eat, then get some hits in. But that also puts you at a constant risk of being knocked to the floor by his heat-seeking frying pan which opens you up to his other attacks, so even that isn't a safe bet.
 * According to the devs of Off The Record, they actually toned down his difficulty for this release.
 * Slappy, who gets around on roller skates and dual wields flamethrowers.
 * The Twins. These lovely ladies take particular delight in mocking you every chance they get, and, despite wearing high heels, run incredibly fast. Oh, and they're equipped with katanas that cleave off massive swathes of health. Have fun!
 * . This boss is INFURIATING if you don't know what to do. Guns are all but useless against him, his hand to hand combat skills will kill you in no time flat, and you fight him on a very tiny platform, from which it's easy to fall off.
 * . He has an excess of health, a next to undodgeable grapple attack that deals huge damage, has a submachine gun if you try to run away, activates fireworks around his boss arena that deal huge damage and stun you, and you're on a time limit the whole battle. But that's not the worst part: the worst part is that all your equipment is taken from you before you begin the fight. The only weapons you can get are a lead pipe and a cordless drill lying around the area. Even if you've learned a bunch of hand to hand combat moves over the game, he's insanely tough to beat.

Devil May Cry

 * The first Devil May Cry had the aptly named Nightmare, an amorphous blob with hard-to-counter rapid fire projectiles and fearsome power and resilience.
 * This trope also apply to the final battle with Nero Angelo in the first game because of his extremely fast and powerful attacks, his highly annoying shield/counter attacks, and his summoned swords, which attack independently in a variety of ways.
 * And that isn't even the hardest fight. Nero Angelo on DMD? Difficult but managable. Nightmare? Lives up to its namesake but not impossible. Mundus on DMD mode? Jesus fucking Christ. No other boss in the series destroys some players with as great a frequency as that thing. Good luck trying NOT to kill him without using any healing items, and especially without relying on an Untouchable.
 * Devil May Cry 3 has, whose One-Winged Angel form was also a blob with hard-to-dodge projectiles. In addition, he could submerge, protecting himself from attacks and summon annoying evil demonic dolphins. The second phase of the fight also stripped the player character of his Devil Trigger Super Mode and Style moves while firing aforementioned hard-to-dodge projectiles even faster, forcing a painfully slow long-range fight. This ones difficulty comes mainly from the fact you cant use your style moves during the fight, greatly limiting your movelist.
 * This assumes Agni and Rudra didn't bring you to the point of hurling your game into the nearest solid object beforehand.
 * Agni and Rudra aren't *terrible* as long as you use Cerberus, realize you can't be aggressive and have to parry (hello, Revolver (2)!) and don't let the combined brother see the light of day (or do so with more than just a minute amount of health). Still hard, but manageable.
 * Devil May Cry 3 also has Cerberus, who was a major cause of returns, resales, and complaints of the difficulty of the game, followed by Agni and Rudra. Cerberus was the boss at the end of the third level(meaning if you died, you probably didn't have enough continue items and had to play the level over) and Agni and Rudra were the end of the fifth.
 * No love for Vergil? In Devil May Cry 3, the third and final fight with him is relatively manageable...on anything other than Dante Must Die, where he will make your life living HELL. He has a metric crapton of health, and all of his attacks from other modes, except they now deal enough damage to kill you in two or three combos, and he gains his Summoned Swords. Not to mention he still has his Super Super Mode from the other difficulties, of which he has two variations. The first consists of rapid teleporting attacks, where he either flash steps above your head to cleave your skull, five times consecutively, with shorter intervals between each strike, or in front of your face to unleash a combo, and he randomly chooses between the two three or four times before going back to normal. The second includes going offscreen while rapid-fire chucking Judgment Cuts at you, which comes in two patterns: The first has each Judgment Cut appear where you stand and can be "dodged" by simply walking around, but GOD HELP YOU if he chooses the second one, where they pop up completely randomly within a set radius around you. It's not rare to jump to avoid one of those damn orbs and then accidentally jump into another one, which carves away about 50% of your full health on DMD. And the worst part is, he regenerates health, without you being able to do a god damn thing about it, and he actually regenerates based on percentage, not health total, meaning that he can easily heal all the damage you did in the last two minutes over the course of ten seconds. And OH GOD, does he spam those moves.
 * Beowulf is also a pain in the ass when he turns re and start throwing cages at you.
 * In Devil May Cry 4 however, That One Boss is clearly and easily identified. In keeping with the Bishonen Line, the rematch with Dante is way, way harder than any of the other bosses. All the other bosses have a pattern. Dante's pattern is to wait until you attempt an attack, then dodge with computerized precision and counter with an impossible-to-avoid attack. Don't even get started on what he does on higher difficulties. You can't even effectively use ranged attacks because he will deflect your bullets by shooting them out of the air. It was cool when he did it in the tutorial level, but as a real boss... ugh.
 * To its credit, though, this fight can look amazing if you get the hang of it. Nothing says "Devil May Cry" like fighting the man who made stylish combat what it is with your own equally stylish attacks. One combo video on YouTube actually ends this battle with both Nero and Dante falling at the exact same moment.

Donkey Kong

 * Queen B in the first Donkey Kong Country game mainly because she's fast and has an erratic movement pattern. She has a good amount of health, and when she takes enough damage, she Turns Red and becomes even faster and much more erratic, meaning you have to have quick reflexes to defeat her. She's even tougher in the GBA port, where she'll summon a gang of Zingers to shield her from your attacks. Not only does it take time to individually defeat each one unless you can spot a TNT barrel throw, they can also spawn in weird formations that make it very hard to safely dodge them.
 * King Zing in Donkey Kong Country 2 continues the trend of bees being tough bosses, mostly because you play as Squawks who is one of the hardest animal buddies to control. You have to shoot at his stinger all the while trying your hardest to avoid getting hit by his stinger projectiles and him running into you because of how difficult Squawks is to control.
 * That's nothing compared to the fifth boss, mainly because his minions keep diving at you while you're trying to attack him, but also because you have to climb up after him when he flies away to higher ground and dodge all of the enemies at the same time. This basically means you have to have Diddy to climb since he's physically stronger and he climbs faster than Dixie - if you lose Diddy along the way, good luck because Dixie's going to need it.
 * Barbos in Donkey Kong Country 3 could very well be That One Boss for the entire Donkey Kong Country series, no question about it. First of all, this fight takes place underwater using Enguarde the Swordfish, which should already tell you something right there. Second, Barbos is a giant Lurchin, which is an underwater creature that can hide inside of its spiked shell and is only vulnerable when it peeks outside for brief intervals, meaning that you have to be quick when you attack her. Third, she can summon an infinite amount of her children, the regular enemy Lurchins, to attack you and protect herself at the same time. Fourth, during the last phase of the battle, she encloses you in a tiny area and moves faster while summoning minions and shooting quills out of her shell at you all at the same time. The only way to damage her is to get rid of the Lurchins protecting her so you can stab her in her soft spot, and the methods you use to do so only become more complex as the fight goes on. Considering the fact you only have a maximum of two hits before you lose a life, this might take a few tries before you finally pull it off.
 * The other bosses aren't to be underestimated either. Arich, the big spider boss from world 2, can only be hurt if you hit him from below with a barrel. His legs, which are long and are spread out widely, can easily break the barrel if they hit it, which they likely will dozens of times during the fight. And after you get a few good hits in, he'll start spitting balls of green gunk that bounce around all over the place, and not only is protecting the barrel from them annoying, but they're tough to dodge in general. And neither Kong has a clear advantage over this fight: while Dixie can safely hit him by letting him crash face-first into the barrels she holds overhead, her and the barrel's combined size makes it even harder to dodge his ball attacks. Kiddy, meanwhile, holds his barrels up front making it somewhat easier to keep the balls from breaking it... but the tradeoff is that hitting Arich, whose weak spot is already tough to properly hit, becomes nightmarish since you have to throw them at a weird, precise angle.
 * Technically Squirt, a giant slug thing and the third boss of the game, can't even hurt you. His one attack, spraying you with a jet of water, causes no damage whatsoever. He's still a nightmare and a half because he doesn't need to properly damage you when he can one-shot you outright: you fight him while standing atop a few oddly shaped platforms set up in a circle, and getting so much as one love tap from his water jets will send you careening off the edge to your doom. And even if you're good at dodging him, platforming in his stage is surprisingly awkward and it's way too easy to overshoot your jump or accidentally run off the platform completely and fall to your death. Oh, and guess what? You have to play as Ellie the Elephant, meaning that you can't save yourself with Dixie's helicopter twirl!
 * Bleak the Snowman is not a straight fight like every other boss, but is instead fought in the style of Swanky Kong's ball-tossing carnival games. So if you've been neglecting those, the sudden shift in gameplay will hurt. But even if you're used to them, he's still a tricky foe: his snowballs come out fast in tricky little volleys, and when he shows off his weak spot you barely have any time to hit him, and whiffing your throw means he starts his Snowball Hell routine all over again.
 * The Final Boss fight against King K. Rool in Donkey Kong Land starts off seeming like an even more predictable version of his boss fight from the original game... then after you deal enough damage, he pulls out the rug from under your feet by suddenly jumping while running back and forth across the stage. His jumps seemingly come out of nowhere and can really screw over people who've committed the original boss fight to their muscle memory. And once you're used to the new timing, you've now got to deal with him charging at you while tossing his crown at you, and he runs fast.
 * Thought King Zing was already a headache in Donkey Kong Country 2? Try his fight in Donkey Kong Land 2, where his gigantic sprite and the Game Boy's small screen are a recipe for disaster. Not only is he far easier to run into than before, but every time you hurt him, he'll summon a few stationary Zingers to serve as living land mines while he chases you. And once you've got him down to low health, he'll zip and zoom around extremely fast.
 * Donkey Kong 64 brings us four of these guys: Mad Jack, Pufftoss, Dogadon (rematch), and King Kut-Out.
 * Mad Jack just looks pants-wettingly terrifying, and that's not the worst part at all - you're forced to fight him on a set of small pillars which must be navigated by using Tiny's Helicopter Hair technique, and if you fall off, you have to sit and wait while Tiny gets dropped off at the top again using a small elevator. He constantly throws fireballs at you with crazy precision, and to damage him, you have to Ground Pound a switch placed randomly on one of the many pillars scattered throughout the room. If you manage to pound the switch and fry him from underneath, he stuffs himself into his box and jumps at you at a rapid pace. If that isn't enough, he eventually turns invisible and jumps even faster, and if you don't keep jumping restlessly away from Mad Jack, he WILL knock you off the platforms. Oh, and he can also activate the energy pillar on YOU if he beats you to it. Mad Jack is insensibly cruel, and to many a fan's dismay, he's only the third boss of the game.
 * Have you played Superman 64? And if so, did you like flying through rings ad nauseum? No? Well too bad, because Pufftoss' boss fight has you do exactly that. To hurt him, you have to ride a hovercraft with god awful controls through a series of rings while the big fish assaults you with shockwaves and heat-seeking missiles. Not only does your vehicle slip and slide like a wet bar of soap, but the rings keep shrinking until you're forced to drive through them with annoyingly tight precision while your hovercraft fights you every step of the way.
 * King Kut-Out is a cardboard cut-out version of King K. Rool, with the ability to shoot lasers at you. You have to jump in each of the cannons on the island, pointed at a spot where King Kut-Out spawns, and shoot yourself at him. He's annoying in this respect because he never fracking stops moving, making him extremely hard to hit. To make matters worse, missing with one of your Kongs flings them into the void behind the arena, forcing you to swap out to another Kong, and if all five miss (not terribly hard to do considering King Kut-Out's erratic movement pattern), you lose the fight and have to start all over again. Even if you do manage to land a solid hit on him, you still have to avoid the blowfish in the moat below (not too difficult, but can still give you quite a bit of grief) and the respawning ghost mook on the central island. With sharp reflexes, he can be taken out quickly, but his laser attacks can still be a pain to dodge.
 * The second fight against Dogadon is probably the most difficult, because of the hard to accomplish objective and time limit to the battle. At first the battle goes like his first fight, but he sometimes throws that goddamn nigh-unavoidable wall of fire at you. Once you've hit him a few times, the platform starts sinking. Then it's all dependent on your Button Mashing as giant Chunky, as otherwise you'll never beat him in time, and the increasingly frantic music doesn't help either...
 * Thugly in Donkey Kong Country Returns. Being a much more powerful version of the first boss, Mugly, he attacks more aggresively and throws fire at different points (including Bullet Hell type). Hard enough to beat the first time, he's an absolute monster in.
 * The Snowmads from Donkey Kong Country: Tropical Freeze make for some of DK's toughest opponents yet, with even the easiest bosses putting up a decent fight. So it should be no surprise that this viking clan's heavy hitters mean business.
 * Ba-Boom the Boisterous is a trio of ninja viking baboon brothers who fight you all at once. They're either swinging on vines towards you at weird angles or filling the arena with bombs, giving you very little room to dodge and safely fight back. While hurting the brothers enough will remove them from the battle, the final brother will eventually summon shadow clone minions to help him out, and if you kill them he'll replace them right away. If you keep your Kong buddy alive (particularly Diddy or Dixie) the fight isn't so bad since their hover and double jump are a big help with maneuvering the battlefield, but once you've taken enough damage and lose them? You're up shit creek without a paddle, because Donkey Kong handles a lot sloppier by himself.
 * Following in Pufftoss' footsteps (flippersteps?) is an even nastier porcupine fish boss: Fugu the Frightening. You have to fight this guy underwater in a cage-like arena with the walls, floor, and ceiling all covered in spiky shells, all while dealing with an obnoxious control scheme and terrible underwater movement. Meanwhile, Fugu's got his own bullshit that he throws at you, usually in the form of suction attacks that try to blow you towards his spiky body or into the shells dotting the walls, or spitting a metric ton of sea urchin enemies at you that you can't hurt unless you've got Cranky Kong tagging along. And to hurt the bastard, you have to attack his spike-less backside, which is a lot easier said than done thanks you having to fight with the swimming controls while Fugu is constantly spinning around. By the end of his boss fight, he inflates himself to the point of taking up half the arena and will start bouncing and rolling around, giving you even less room to dodge his attacks than before.
 * Lord Fredrik is the king of the Snowmads, and definitely lives up to the hype. You fight him in an arena over a pit of insta-kill lava, and his jumping attacks will submerge parts of the floor into that lava, creating massive death pits for you to leap across. He can also summon a hail of ice dragons that will try to crash into you from above and will leave the floor frozen and slippery upon making impact with it, which make it even harder for you to hit him during the brief moments where he's vulnerable. But even without the slippery floor, hurting him is a tall order since you have to jump on him while he's running around at Mach 5. Miss your jump, and you're very likely to get crushed underfoot by this Fat Bastard of a walrus before you can get out of the way.

Hollow Knight

 * Miniboss he may be, the Soul Warrior is bound to be the first true speedbump you run into while playing through Hollow Knight. Despite being nearly as big as the False Knight, he's faster than Hornet and even more aggressive than her. No matter where you stand in his arena, you're never safe: his dash attacks allow him to close the distance in the blink of an eye, he can fire homing projectiles at you, and he can even teleport above you and squash you under his massive body. If you walk into this fight expecting another fairly easy Giant Mook battle, you’re in for a very rude awakening.
 * If you want the Shadow Soul, you'll have to go through a second Soul Warrior to get it. He's just as tough as the first, except he's got a never-ending flood of Flukes flying in to get in your way! Easy to kill as they may be, they have an annoying tendency to spawn right on top of you or directly in your path while you're dodging or trying to attack him.
 * And if you thought the Soul Warrior was a doozy, get a load of his boss! The Soul Master Teleport Spams like a motherfucker and often follows up by slinging homing spells of his own at you. This strategy makes it hard to safely hit him, but it's not the worst part of his fight. The worst part is his dreaded ground pound attack. This attack comes out fast, and if you manage to safely dodge you can still be hit by the fast-moving shockwaves that it generates. He'll even play mind games with you by throwing out a bluff attack, only to instantly follow up with a real ground pound that is almost guaranteed to crush you if you dashed out of the way of his fake-out.
 * Once you get access to his rematch in the dream world, the Soul Master, now the Soul Tyrant, is an even more frantic boss whose attacks come out even faster than before while his spells come out in different, tougher to dodge patterns. Oh, and his Teleport Spam is even worse, if that's even possible.
 * While you can postpone their fight for a while, you'll have to tangle with the Mantis Lords sooner or later. And no matter when you fight them, they're no joke. It isn't so bad at first since it starts as a duel against a single Lord, but once you defeat her, the other two decide to team up against you. Now you've got to deal with the nightmare that is two speedy opponents attacking you in quick succession. Your health will plummet because of how easy it is to dodge one Lord only to accidentally run right into the other's incoming attack, and that's assuming she doesn't simply telefrag you or trick you into falling into the spikes on the edge of their stage. Sad thing is, they aren't the worst example of a Dual Boss in this game...
 * That would be the Watcher Knights. Their boss fight is a brutal gauntlet against 6 beetle warriors that take you on two at a time. And unlike the Mantis Lords who at least have a sense of rhythm to their attacks, the Knights' fight is a total clusterfuck where they throw out whatever attacks they want, whenever they want. The deadliest tool in their arsenal has them roll into a ball, and either try to run you over by blazing a trail across the battlefield, or bouncing into the air and crushing you under their girth. There's no telling which version of the attack they'll use until they go in for the kill, and because they don't synchronize their attacks you can end up in a lot of situations where you get cornered while dodging one attack and get squashed flat by the other, or get nailed with a sudden bounce attack because you jumped over a Knight that was trying to squish you into goo.
 * You can fight the Brooding Mawlek a little after the beginning of the game if you know where to look, but just because you can fight it early, it doesn’t mean you should. It's a ruthless, daunting opponent who never lets up with its attacks, and spews a metric shitton of acid all over the place while slashing at you with its claws if you get too close. It can also randomly go on a bouncing frenzy and smash you into paste if you aren't on top of your dodging game. While none of this changes if you fight it later on, you'll have plenty of tools to even the odds while an underequipped newbie will have no such comfort. And if you haven't upgraded your nail, you've got a boss that's every bit as meaty and long-lived as it is aggressive.
 * The first fight with Hornet was a tough but manageable skillcheck to see if you understood how the game’s combat mechanics work. So when you encounter her in Kingdom's Edge later on, she throws whatever little mercy she showed you out the window and stops holding back. She's far more nimble and aggressive than before, and once she's lost enough health she starts setting up spike traps around the arena. They may be flimsy and easily broken, but in the heat of battle you're far more likely to pay attention to the total spaz that is Hornet than you are the traps, and the battlefield's weather-induced Interface Screw makes it easy to lose track of them until you've faceplanted right into a ball of spikes.
 * The Traitor Lord is much more acrobatic than his massive size indicates, making it jarring when this big bug suddenly launches himself at you and lops off two masks worth of health in the near-literal blink of an eye. All of his other attacks deal just as much damage, which is scary since his fight is set up in a way that you're guaranteed to be weakened by the time you get to him: you have to navigate a treacherous path full of spiky brambles and kill a wave of his Traitor Mantis brethren before he even shows up. Completing Cloth’s questline does ensure that she’ll help take the pressure off of you during the enemy rush, but you've still got to do most of the heavy lifting during the boss fight yourself since she's very unlikely to hit him.
 * So you saved Zote's ungrateful hide and defeated him in the Colosseum of Fools, only to have him steal your fangirl's affections as revenge. Thankfully, you can screw him over right back by defeating the idealized Zote that said fangirl dreams of. Sounds easy, right? Oh ho, BOY, are you wrong. Said idealized Zote is easily one of the game's hardest boss fights and is an utter mess of RNG-induced bullshit.
 * Grey Prince Zote has an attack pattern that can only be described as "schizophrenic". He'll run around like a headless chicken before throwing out attacks such as shockwave generating ground-pounds, triple bounce attacks with inconsistent distances between bounces, a rapid sword-swinging attack that he can suddenly cancel into a shockwave-generating faceplant to punish your pogo jump attacks, and obnoxious enemy summons (some of which can EXPLODE). Many of these attacks have little in the way of tells, are sometimes accompanied by feints to mess with your dodge timing, and are almost guaranteed to hit you depending on which ones are chained together. While you only have to defeat him once to collect Dream Essences from him, getting revenge on him properly requires defeating him four times. And each version of Gray Prince Zote gets stronger, culminating in a fight where every attack hits for two masks' worth of damage.
 * And if you're a total masochist, you can keep fighting him even more! His strength keeps growing with every fight. And the last fight will have him deal eight masks of damage with every hit. If you haven't maxed out your health, any attack from Gray Prince Zote is an instant kill. And at that point, you might find yourself reexamining your reason for fighting this douche. Is the Bragging Rights Reward REALLY worth it?
 * It speaks volumes that the devs consciously made him the ONLY boss you can actually remove from Godhome's boss rushes just because he's THAT prone to killing you with complete bullshit. No other bosses, not even notorious ones like Markoth or Nightmare King Grimm receive such an honor.
 * If you've been struggling with the bosses during normal gameplay, wait until you get access to the Dream Needle. With this technique, you get access to rematches with a few bosses that are much harder than before. The Soul Tyrant's covered above, but as far as the others go?
 * The Lost Kin. In some ways he's easier than the Broken Vessel since he loses his Bullet Hell attack. Even his newfound aggression wouldn’t be bad, but much like the Soul Warriors he has a never-ending stream of Infected Bubble Mooks pouring in. They're annoyingly good at setting you up to get hit by the Kin, but they're also prone to spawning right on top of you, wearing you down or finishing you off just because you happened to be at the wrong place at the wrong time. The Defender's Crest is damn-near essential for this fight, but even it doesn't grant you a guaranteed victory.
 * The Failed Champion takes the False Knight's boss fight and turns it into a frantic, chaotic nightmare. Formerly a textbook example of a Mighty Glacier, he's now a vicious Lightning Bruiser who constantly leaps all over the place while generating tons of shockwaves with his hammer swings, which are much more frequent than before. The rocks that fell when the False Knight would periodically flail his hammer around now fall constantly, from the start of the fight to the end, and there is nothing more frustrating than getting clipped by a random rock when you had the Champion right where you wanted him.
 * Nightmare King Grimm, the True Final Boss of the Grimm Troupe DLC mission lives up to his namesake, alright. Insane speed and aggression? Leaves trails of fire in the wake of certain attacks? Can force you to sit through uninterruptable Bullet Hell intervals? Erects a massive wall of thorns with stupidly tiny safe spots? Takes off two masks of health with every single attack? If you don't banish him beforehand, get ready for a truly hellish fight that you can lose during the first five seconds. And even once you get used to him, the slightest mistake can quickly lead to things snowballing completely out of control.
 * Nightmare King Grimm, the True Final Boss of the Grimm Troupe DLC mission lives up to his namesake, alright. Insane speed and aggression? Leaves trails of fire in the wake of certain attacks? Can force you to sit through uninterruptable Bullet Hell intervals? Erects a massive wall of thorns with stupidly tiny safe spots? Takes off two masks of health with every single attack? If you don't banish him beforehand, get ready for a truly hellish fight that you can lose during the first five seconds. And even once you get used to him, the slightest mistake can quickly lead to things snowballing completely out of control.

Kirby

 * Meta Knight is usually difficult to defeat in a majority of the games he's in, due to the fact that in a majority of his fights you can only use the Sword against him. For those at home not familiar with the mechanics of Kirby games, Sword is a power focused around melee attacks with little in the way of range, meaning that you're forced to get right in the face of one of the most aggressive and nimble bosses in the series in order to hurt him, with his short size making it even harder to get a hit in. He also carries an arsenal of devastating attacks such as the Mach Tornado, where he envelops himself in a cyclone of pain and homes in on you, or his standard Tornado attack which whips up a twister that travels a huge portion of the arena - at low health, it will hit you if you don't get behind him before he unleashes it. Little else in the series measures up to the difficulty of these duels, and even fights where you do have access to your Copy Abilities still tend to be difficult.
 * Kracko in many games, starting with the Extra Mode of the original Kirby's Dream Land. Lightning fast, with a completely different attack pattern that gives you next to no time to react. His weaker Kracko Jr. form is just as hard, and some think he's even harder to beat - again, Extra Mode transforms a once easy boss into a spastic nightmare who is constantly bombarding you with bombs and cannonballs, and that's when he isn't trying to charge into you outright.
 * Of course, in this game getting to him means first getting through Kabula, who was a pushover in the regular game - but in Extra Mode she becomes the most insane, random, frantic battle in the game. Beating Kabula on Hard is as much luck as anything else. While they tried to replicate the difficulty in her later appearances (Kirby Super Star Ultra and ) nothing can compare to the original. Between her Bullet Hell patterns and ridiculously quick ramming attacks, that thing is a MONSTER.
 * Whispy Woods of all bosses is a monster in Extra Mode. Iconic for being one of the most prolific easy bosses in any Nintendo game, Whispy's suddenly a lot scarier when most of the apples he drops onto you are replaced with the indestructible spiny Gordos. They lop off a whopping 3 health if they hit you. You have six health. They bounce a bit when they land, can block your shots, and can corral you right into the path of Whispy's wind attacks. You see the problem, yet?
 * Kracko could be regarded as kind of a junior version of Death and Ridley, in that he's in most of the games with the same patterns and strategy, but is somehow usually one of the harder bosses (which, admittedly, isn't always a strongly contested title in Kirby games). Cloud levels tend to be a bad sign...
 * There is one exception: Kracko doesn't appear in Kirby Squeak Squad. Oh no, instead, you fight Mecha Kracko, piloted by one of the titular Squeeks. While he's annoying enough on his own, once he Turns Red he starts using an attack where he moves towards the bottom of the screen, destroys the stage, and reforms it later. If you don't take to the air in time, you will die from this attack. Regular Kracko may be annoying, but at least he doesn't use an attack that can cause a one-hit KO at regular intervals. And this is the only boss in the game that has TWO health bars to drain. Not even the final boss has two health bars.
 * Paint Roller is considered this by some in Kirby's Adventure and its remake, Kirby: Nightmare in Dream Land. Being a fairly unpredictable quick target that many abilities don't work on will do that, but not to everyone. The fight Kirby: Canvas Curse is probably the most irritating boss in the entire franchise, though. The matches required to get through the main game are not very hard, but the ones required to get all the collectables are frustrating, much less with a grade A score.
 * Heavy Mole is even harder. For starters, he's fought in an auto-scrolling stage full of instant deathtraps such as bottomless pits and walls you can get crushed against. And if you don't bring a copy ability into the fight, the only ones you'll have access to are Hammer, which risks breaking the ground and dropping you to your death, and Sleep, which is useless and leaves you a sitting duck while the autoscrolling screws you over. Thanks to these being your only options, you're honestly better off just spitting his missiles back at him.
 * Rolling Turtle/Phan Phan (depending on the version) is surprisingly vicious for a Mid Boss. He's incredibly aggressive and constantly jumping around unpredictably, and his painful grab attack has a deceptive amount of range to it. The devs got the hint come Superstar Ultra, and toned his aggression down there.
 * The "Helper to Hero" mode in Super Star Ultra delivers a few of these, but especially Meta Knight as Bugzzy. The only way the Knight can be hit, discounting the aerial kick he usually will jump out of the way of, is to grab the stars he leaves behind after certain attacks. Problem is, these stars can be impossible to get unless you're in specific spots (as one of these attacks takes nearly the entire screen and can't be dashed through). The one upside there is is that the stars do a good amount of damage so you won't need that much to beat him. Again, good luck getting them.
 * Galacta Knight is pathetically easy when fighting him with Meta Knight during Meta Knightmare Ultra in Kirby Super Star Ultra, due to Meta Knight's healing move, Mach Tornado, and overpowered moveset. Then comes the fight with Galacta Knight as the penultimate boss of The True Area with Kirby, and suddenly he doesn't seem like such a wimp anymore. The player probably has low health by the fight, has to conserve health for the next boss, and cannot heal or abuse a super move like the Tornado. Worst of all are Galacta's Flail Knights, who, unlike the other Mooks he summons, are constantly attacking with a long-ranged weapon that hurts.
 * Adeleine/Ado from Kirby's Dream Land 3 may look like an adorable and harmless little girl, but don't let her cute appearance deceive you. Her fight is a grueling Boss Rush where you fend off all the non-Dedede/Dark Matter bosses from Kirby's Dream Land 2. The Ice Dragon isn't so bad, but things start to get intense when she doodles Sweet Stuff, who can fire electric blasts that home in on you. Her Mr. Shine and Mr. Bright sketches are next, and you're forced to contend with two opponents at once; when you kill one, the second will aggressively charge after you until he falls. And once they're taken care of, she sics Kracko on you, who is every bit as dangerous as he usually is. Thankfully, once you beat him you're in the clear: there's one last phase, but it's Ado uselessly flailing around at you, and even your dash attack/exhale can knock her out in one hit.
 * The True Final Boss is a hell of a note to end the game on. Like with Ado, he has multiple phases that you have to do in one go, with no healing in between. The boss fight is also an Unexpected Shmup Level where Kirby is slow, but he isn't. And his attacks involve trying to ram into you with his massive body, disappearing from the screen only to quickly home in on you from the background while shooting torrents of blood, and pelting you with tiny  that love to get in the way. Once you think you've won, . The first phase, while far easier than the ones that follow, can still be annoying if you don't realize that.
 * Miracle Matter in Kirby 64: The Crystal Shards has seven forms representing the different abilities in the game, each of which can only be harmed by using an ability that matches it or by sucking up his projectiles and spitting them back at him when he uses the same ability as the projectiles you inhaled, and it must be done quickly before he changes back to his main form - anything that doesn't match the ability Miracle Matter is using will have no effect. Speaking of no effect, his main multi-eyed dice form is completely invulnerable. All seven of his ability forms have to take at least three hits from their projectiles in order to be destroyed, and worse yet, you have to face all seven, which easily makes this boss battle one of the longest and toughest in the game. While some of his forms are harder to deal with than others, Ice and Bomb are the worst: when he's using his Ice form, he's surrounded by a ring of ice blocks that are deceptively hard to dodge thanks to the way they rotate and undulate around the 3D axis in a 2D game. Bomb, meanwhile, has him attack you with four large randomly-moving bubbles that split into eight smaller bubbles, with their random movement making it easy to accidentally faceplant into one while you're trying to dodge.
 * Who remembers Mega Titan from Kirby and the Amazing Mirror? It’s a flying robotic suit of armor at least four times bigger than Kirby, with four detached (and also flying) metal hands that were the size of Kirby himself. It attacks by using its hands to hound Kirby and his friends around the room which is already tight for space with Mega Titan’s size. You cannot stop the hands, and they will relentlessly pound you from every direction, sometimes all four at the same time. The only way you can get the Mega Titan take damage is by knocking its main body into the electrified walls on the sides of the room or using the Beam or Spark Copy abilities – and that’s easier said than done. Normal attacks barely move it back, and the Mega Titan’s body tends to hang around the centre of the room, meaning it takes 2-3 normal hits to smack it into the wall - and during that time, you’ve probably been ganged-up on by the Titan’s hands and taken some damage. And to add to the grief, this is the only boss aside from the Final Boss that has more than one phase: destroying the main body leaves behind the Titan Head, which can thankfully be damaged normally, and two hits make it history. However, Titan Head is smaller and moves in an erratic zigzag pattern around Kirby - who is probably low on health by now – firing missiles and trying to ram into the poor little spud.
 * Goriath from Return to Dream Land. He wall clings just above the range of a lot of vertical attacks, forcing you to jump to get to him - and sometimes he'll decide he's going to drop down on top of you, so if you're jumping under him and/or the floor is icy, he will hit you. If you're in the air when he jumps from one side to the other, he WILL jump right into you. When the floor breaks and gets icy in his second phase, it becomes easier to avoid his Ki Attacks and giant punches, but harder to get away from body slam, that flying tackle, and the exploding spiky ice balls. And he's so damn fast and jumps around so much that he's hard to hit. For, and most other hard Rt DL bosses, dash attacks with invincibility frames are very effective - but Goriath's floor changing and wall clinging make them useless at best, so you'd better get used to fighting a different way.
 * So you're playing Extra Mode, and are doing pretty okay. Whispy Woods EX was as easy as ever, Mr. Dooter EX puts up a decent fight but nothing spectacular... and then Fatty Puffer EX bitch-slaps you into next Sunday. Building off of the original Fatty Puffer's formidable fighting style, EX is an overwhelming nightmare who inflates himself to the point that his rolling attacks are nearly impossible to avoid, and can roll up walls and across ceilings while inflated at such a high speed that Kirby has barely any time to dodge it. His water beam is even more powerful than the original Fatty Puffer's, comes out with little warning, and can be aimed at upward and downward angles. And sometimes when he's on the ceiling, he'll shoot a spread of water blobs that are positioned and angled at a way that makes them really tricky to dodge.
 * Grand Doomer was a decently tough Disc One Final Boss and fairly manageable, but Grand Doomer EX will make you want to cry. He fights a lot like Kracko, complete with aggressive swooping/divebomb attacks, but throws his own attacks into the mix, such as a fast-moving grab attack that deals impressive damage to your dinky little health bar, and projectile spam to the point that his fiery blasts can cover most of the screen. The True Final Boss, ? A cakewalk compared to this guy.
 * Dubior EX takes an already annoying miniboss, and makes it completely unbearable. Along with its annoying Teleport Spam tactics, aggressive lightning bolt attacks, and constant flight, its new tricks include a really wonky electrified tackle that is hard to wrap your brain around the first few times it uses it, and another lightning tackle that moves blindingly fast.
 * Metal General EX is this for many, due to an unexpected event during the fight. He starts out as a buffed version of the regular fight, like all the other bosses, and everything seems fine and dandy when you beat him... Until he suddenly gets a gigantic robot: HR-D3. While it is easy to dodge once you get the hang of it, hurting it and dodging at the same time is hard to do thanks to its weakspot (its arms) only being vulnerable while it's attacking, and with fast-moving slaps to boot. Also, guess what? Once you do beat it, yet another phase begins. Its attacks are extremely difficult to dodge, one of them notably being a belly flop that covers half the screen, and you're likely weakened from the previous phases. If it weren't for the fact that you don't have to do all of the fights consecutively, people would have ragequit the game before even reaching the final level. One last thing, he has more phases than the final boss. Have fun.
 * Kirby Triple Deluxe:
 * If you thought Kracko was hard in previous games, this game is easily his most brutal outing yet. Not only is he as aggressive and unpredictable as ever, but he's got a massive arsenal of attacks he can throw at you in his second phase. He can pelt you with a storm of garbage, hit you with an undodgeable screen-covering barrage of lightning if you don't escape to the background/foreground (depending on which plane of the battlefield he's currently on), run you over with a ridiculously fast drill-powered body slam, or launch a massive ball of lightning at you that splits into four smaller projectiles. He's even worse as Kracko DX, where his speed, aggression, and unpredictability are cranked Up to 11. When the pause screen warns you about Taranza's magic making him stronger, it's not kidding.
 * Very few Kirby bosses are as hated as Pyribbit, and that's because he's the unholy union of this trope and Goddamned Boss. Like all of this game's bosses, he can hop into the background and pelt you with attacks while you can't punish him. But he's by far the boss that abuses this mechanic the most and will often leap into the background every few seconds. This alone would merely be annoying, but when he bothers to fight you face-to-face, you quickly realize that he's way more aggressive and mobile than his blubbery body would suggest. When he isn't trying to squash you under his weight with his body slams or cutting off your approach by setting parts of the ground on fire, he's chewing you up and spitting you out for a ton of damage with a blindingly-fast tongue attack that he can aim. When he Turns Red, he'll spend even more time in the background by sending multiple waves of lava monsters you way, and you're given very little wiggle room to safely dodge them. And like with Kracko, Pyribbit DX is even worse than the original thanks to a boost in speed and aggression.
 * Normally, Blocky is a manageable miniboss. Aggressive and surprisingly fast given his large and cubical frame, but nothing too crazy. But thanks to the lava ceiling restricting your movement during a fight early into Endless Explosions, Blocky's fast-moving dash attacks and body slams make him a force to be reckoned with. Not helping matters is the fact that he can still hurt you when you dodge his attacks, on account of the damaging rocks they kick up.
 * During the Boss Rush at the end of the game, it's not the Final Boss that's the biggest threat, but the fight that precedes her: . His first phase is your standard easy fare, but when the second phase starts, he becomes a terrifying Lightning Bruiser that fights like an axe-murderer on crack. His brutal spin attacks turn him into a bladed whirlwind that hurtles across the entire screen in half a second, and one of them will even home in on you. He also has some nasty projectile attacks that home in on you as well, while others have him trip you up by firing them directly into parts of the screen that most players retreat to during his other attacks. The nastiest of the bunch though is a gigantic blob of dark magic that bounces awkwardly across the screen like Pyribbit and Fatty Puffer's equally annoying body slam attacks, and is just as tricky to dodge. And again, his souped up form  takes an already relentless boss and makes it even moreso.
 * Kirby Planet Robobot:
 * King Dedede usually isn't a particularly hard boss during his boss fights... so instead, Haltmann Works' Dedede Clone is more than happy to pick up the real McCoy's slack. The fight isn't too bad at first, since the clone fights like a somewhat more aggressive Dedede. But once you lower his health down to half, he dies... and splits into three. All of a sudden, you're being mobbed by a trio of hyper-aggressive clones that will pummel you into submission with wide-reaching group attacks, before de-synching and taking turns beating you black and blue before you even have a chance to recover.
 * Dubior EX (or as it's called here, 2.0) is back and just as spastic and unpredictable as ever. But along with its constant teleporting and hard-hitting electric attacks, it throws in some Goddamned Boss flavor by warping to the 3D plane where your attacks can't reach it a la Pyribbit from Triple Deluxe. Even worse is that it shows up way earlier than intended if you're going for 100% completion, and its early fight takes place on a giant pool table where huge billiard balls are constantly rolling in from the background and trying to crush you.
 * Much like in Super Star Ultra, is easy as hell when you have Meta Knight's arsenal of Game Breakers on your side, but utter hell in the True Arena where you have to play as Kirby. Once again, he's an aggressive and intelligent foe who will happily nullify whatever attacks you pull out with his shield before brutally punishing you with a hard-hitting attack. He also learned a few new tricks since his last appearance, such as creating a massive storm of sword beams that are ridiculously hard to dodge unless you luck out and find the two safe spots that they can't reach, and a disgustingly fast dive bomb attack that will hit you unless you dodge the second he flies to a certain spot in the background. And while it's not so bad once you learn how it works, the attack where he cuts open a portal to Another Dimension and unleashes a massive laser beam will blindside you the first few times you fight him. Beat him, and chances are you'll be horribly worn down just in time for one of the biggest examples of That One Boss in the game, if not the entire series...
 * Said boss, of course, is, the obligatory Soul version of a final boss fought at the end of several games' True Arena. This fight is a grueling, arduous duel that goes on forever and stretches across four (technically five) phases. If you don't come in with full health, chances are you simply won't survive all the bullshit it throws at you. And even if you do, you're in for a brutal and stressful fight.
 * Its first two phases are manageable, but it throws way more lasers at you as well as some scary new attacks that include wreathing itself in fire and chasing after you, a faster and longer-lasting version of its hard-hitting limb swipes, and another attack where its severed limbs close in on you and try to crush you while you have very little room to safely dodge.
 * Phase 3 is a frantic race against the clock where you're hoping and praying that you'll kill before it finishes its countdown. Because if it does, it unleashes a Fatal Error attack that will instantly kill you unless you pull off some insane perfectly-timed dodge rolls through the barrage of death screens. To avoid having this happen, you need to destroy as many of its  as possible so you can use their debris to power your Robobot Armor's obscenely strong combo cannon. But of course,  doesn't want to make this easy on you - not only do these summoned items hit hard and fight with weird attack patterns, but every time  counts down it assaults you with a massive electronic number. 5, 4, and 3 aren't so bad, but 2 and 1 move in weird, inconsistent ways that will lead to a lot of lost health unless your instincts are on point.
 * And if you somehow survive all of this, you have Phase 4 to worry about! . And the first phase is a lot like in the sense that you're having to dodge through and destroy pillars powering up the boss... while they move at random speeds and try to crush you between each other for some nasty collision damage, which can really screw you over depending on Kirby's current ability. Then when you reduce its health to half, phase 5 begins, and the  will aggressively teleport like crazy before smacking you with its wide-reaching, fast moving attacks. The erratic and chaotic nature of this phase will lead to plenty of unfair deaths before you finally beat it...
 * What makes this especially infuriating is that.
 * Kirby and the Forgotten Land:
 * You may not expect much when you first encounter Sillydillo, which makes it a huge shock when that goofy-looking armadillo flattens you into paste. While his first phase is nothing to write home about, phase 2 has him spam a rolling attack that hits hard and can easily trap you if you dodge the wrong way in his surprisingly small battlefield. But even that doesn't hold a candle to phase 3, where he ballroom dances all over the place with a scrap dummy. His movements here are chaotic and unpredictable, and when he's done? He starts spinning several dummies your way, and they home in on you! And the cherry on top is the fact that he immediately follows up with more rolling attacks, and the dummies are annoyingly good at corralling you right into his path. If you haven't mastered the dodge mechanic, you're not getting past this guy.
 * And if you think merely fighting him is bad? His extra challenges are even worse. One tasks you with killing him, a boss whose strategy revolves around running away from you and making it unsafe to approach him, in under two minutes. Another? Beat him without getting hit. At all. While a lot of his attacks require near-frame perfect dodges to avoid. You can't even cheese the fight with the Drill ability, since some of his attacks can hit you underground!
 * Phantom Sillydillo, who's fought in the postgame is more-or-less the same, but with two new tricks to make him even more of a pain: he whips up a sandstorm in phase 3 in order to screw with your visibility, and he no longer gets dizzy after his rolling attacks. At least you don't have to worry about not getting hit/killing him quickly.
 * The transition into 3D has given us some of the franchise's toughest Dedede fights yet, with the pinnacle being the nightmare that is Phantom Forgo Dedede. He's an aggressive spaz who rarely ever stops moving and almost every attack of his generates either a fuckton of fire tornados or dangerous trails of lava. The lava is especially annoying because if you're using a copy ability with limited range like Sword or Needle, attacking him is very unsafe thanks to him often going idle smack-dab in the middle of it. Certain attacks of his will also mess with the arena, knocking it on its side and submerging it in a pool of lava. Not only does this cut off access to half the arena, but gravity will constantly push you down towards the pool.
 * Leongar was already a fairly formidable Climax Boss during the story, so he gets quite the upgrade during the postgame. In an interesting twist of fate, Forgo Leon’s fight is a reverse of his original boss fight: he starts off in his berserk state, where he assaults you with powerful attacks that have insanely good tracking, such as a long-lasting series of ferocious bites and an energy beam. But once phase 2 begins, the fight turns into a much more complex version of the original Leongar fight’s first phase. Here, Leon’s attacks start generating massive shockwaves, as well as damaging trails of lightning and fire while his claw beams come out in far more complex patterns than before. also becomes an active participant in the fight, and will back up Leon’s unrelenting attacks with massive arena-spanning blasts and annoyingly accurate projectiles of its own. The combined might of the King of the Beasts and  is bound to give even the most hardened of Kirby veterans a hard time.

Mario

 * Super Mario Bros. 2 has Fryguy, the flaming entity fought in World 4. At first, it seems like you simply have to hit it with the mushrooms three times, and technically that's the idea. After that, however, it splits into four living fireballs that hop here and there, trying to hurt you. And the more fireballs you kill, the faster the remaining ones will move. Granted, it's possible to kill them all in one hit, but good luck with the timing. To make matters worse, the game had a glitch where if you touched the last fireball before it died, the door to the next world might not appear. (You could escape having to reset by using a code that killed you, but that just meant you had to try and beat this boss from the beginning.)
 * Clawgrip is no pushover either. The rocks he tosses at you are awkward to grab, and he can toss them in hard to dodge volleys that make fighting him as someone other than Peach hell on earth. Though even she is far from a safe bet, since he can still bonk her with a rock during her long picking-up cycle.
 * Wendy Koopa in Super Mario Bros 3 is way worse than her brothers. While the others' attacks will fly offscreen, the rings of energy she fires will bounce round the room endlessly, and she'll keep adding more. If you can't stop her before there are more than three or so, you're not going to.
 * Roy and Ludwig are also tough, mainly for their nasty gimmick: these guys are so heavy that they cause the ground to shake when they land after a jump. If you're on the ground when they land, you're briefly stunned and helpless against any attacks they'd follow up with. And since the elevation in their boss arenas is really uneven, you're constantly having to carefully time your jumps to dodge their own quake jumps, while also dodging the wand blasts they fire at you. And if that wasn't enough, their airships are among the hardest in the game meaning that you'll likely be fighting them after being reduced to your One-Hit-Point Wonder form.
 * Give Wendy a shot in New Super Mario Bros. Wii, too. Essentially the exact same fight as SMB3, but underwater. If you don't have a Fire Flower on hand, you're going to have to wait it out when the rising water prevents you from jumping on her.
 * Luigi's Mansion has Boolossus, the game's third boss who seems simple enough on paper: you pull the enormous Boo to a unicorn statue to pop him, freeze the fifteen Boos that split up, and suck them up to win the battle. However, vacuuming up the smaller Boos is incredibly tricky because they get harder to hit with your ice attack the more you suck them up, and they attack by dashing into you at high speeds which are incredibly tough to dodge. Collecting the final few Boos is a chore to do because of this, and getting a gold rank on him (which means not taking any damage) is a nightmare.
 * Super Mario Sunshine has Sirena Beach's Phantamanta, a giant manta ray that leaves behind electric goo and divides every time you hit him, up to a maximum of 64 little mantas that you'll have to vanquish. Even worse, when there are only tiny mantas left, they will start chasing you. Be careful not to step in any goop when going to refill FLUDD!
 * You can make the battle slightly easier by first dividing the manta into roughly four, then focus on dividing and killing one part at a time. You can also hide under the cabana roofs to prevent it from reaching you, since the "mantas" are actually ghostly silhouettes that float on top of whatever terrain they encounter. Once they float over huts or trees those parts of their silhouette will therefore appear on top of the object.
 * Cleaning Eely Mouth's teeth is annoying, as you're underwater with HORRIBLE controls, and you have to be dead on when firing at his teeth to clean them. Also, your life is slowly going down, and it's not obvious that you can use the bubbles to regain your health until it happens by fluke, and it takes a looong time to get low enough to hit him properly. Even if it is dead on, you have to be low enough for the water to hit his teeth to actually count.
 * Hookbill the Koopa from level 4-8 of Yoshi's Island. Easy like everything else when you play it normally. But when you want the 100 Points, you're not allowed to take damage even once. And this boss has really bad attacks, heavy collision damage, and don't forget that you have to wait 30 seconds when you get damaged! Prepare yourself to repeat this boss over and over again for 100% completion.
 * Bouldergeist from Super Mario Galaxy doesn't appear to be this trope at first. In fact, he easily qualifies for Best Boss Ever status thanks to the complexity of his battle and the satisfaction that comes from slamming Bomb Boos into him. And then the Daredevil Comet comes into play, and he's suddenly a lot less fun. The stone spikes that can cut off your mobility are a pain in the tail when you're trying to dodge his rock barrages or giant fists, and when you can't take a single hit due to the mandatory 1 HP in daredevil challenges, saying "fuck it" and tanking an attack is no longer an option. Said fists can also eat up attacks meant for his body, and as far as that goes, he's sturdier than just about every non-Bowser boss and takes six hits at the minimum to bring down.
 * Fiery Dino Piranha is also really bad. If you thought you were due for an easy time since he's a reskin of the first boss, you are VERY wrong: unlike the original Dino Piranha whose tail you could whack whenever you felt like, F.D.'s tail is constantly igniting and burning out, meaning that without proper timing you'll hurt yourself instead of him. And if that wasn't already annoying, he's a lot faster than his weaker cousin meaning that even if you have the timing down, you can still be thrown off by trying to keep up with him. And then, there's the trails of fire he leaves behind which gives you another threat to worry about... and that's before the fireballs he spews during the final phase come into play. And on top of that, his tendency to suddenly turn around right when you try to attack his tail means you can do everything right and still get punished for it. The devs were likely aware of how aggravating he is to fight, because the Melty Molten Galaxy's Daredevil comet is the only one of its kind that doesn't make you fight the boss with one health.
 * None of the fights against Kamella Koopa are particularly bad... save, of course, for the Deep Dark Galaxy Daredevil run. When she moves up to the ship's crow's nest, you have to fight her in a very cramped arena where she and her Magikoopa minions are all pelting you with fire spells. Her massive size also makes it easy for her to Tele Frag you up there.
 * The Toy Time Galaxy's Undergrunt Gunner fight is a far cry from his usual easy battles, because his cannon fires lightning balls that home in on you, and you're forced to fight him while playing as the unwieldly and awkward Spring Mario. Do the math, and the results aren't pretty.
 * Fire Gobblegut from Super Mario Galaxy 2. He's annoying enough in his regular form, but his fire version takes it to the extreme. You can't touch his body without taking damage, making it very hard to take out his belly bulges during the short window you have open to you, and whenever he dive bombs the planet, he leaves lava pools. After the first three hits, it starts raining fireballs.
 * Also from Super Mario Galaxy 2, Squizzard. Fought in the middle of a sand whirlpool that constantly sucks you towards him unless you're standing on one of many tiny rock platforms. Throws giant rocks (and after you damage him once, spiky balls) at you, which STAY THERE after they land until you destroy them. His weak point is his mouth, which he opens for half a second BEFORE throwing his last projectile (so by the time you've dodged it, he's closed his mouth again - you have to shoot at him and THEN dodge). You can only damage him using the (temporary) Fire Flower powerup, and you have to hit him five times (in quick succession, or he'll close his mouth and you'll have to start again) in order for one damage point to register on him. And when he's down to one damage point left, he gets these turret things on either side of him, that shoot balls at you EVEN WHILE HE'S STUNNED. Not to mention the balls get in the way of your fireballs. And - like the Bouldergeist example mentioned above - you have to do a perfect run on him if you want 100% Completion.
 * Surprisingly, Peewee Piranha becomes this in his associated Speedy Comet mission. It's not that he's a powerful combatant, but his fight is a Race Against the Clock where you're pitted against a foe who's very good at wasting what little time you have. His mobility makes it hard to land a hit on him, and he's prone to leaping away from you or turning around right when you're about to hit his weak spot. This gets truly ridiculous when he's on his last legs, because he'll sprint around the planetoid arena like Usain Bolt and make it nearly impossible to finish him off before you time out and die.
 * Bouldergeist and Fiery Dino Piranha both make a comeback in the Boss Blitz Galaxy, and are even fought back to back! They're the last bosses you have to fight, and retain everything that made them annoying to fight in the first game. Thankfully there's no Daredevil comet involved... but there is a Speedrun challenge that gives you five minutes to defeat every boss in a row, these two included. And whether it's Bouldergeist's hands shielding his body from harm or FDP's... everything, you bet that every death will happen because you timed out on one of these bastards.
 * New Super Mario Bros. 2 is a very easy game, but Ludwig can be tricky. He'll dangle from a chain hanging from the ceiling, and to hit him, you have to launch yourself at him from a cannon. And at first, it's easy to hit him. But after the second time you hit him, he'll start wildly swinging around on whatever chain he's latched onto, and all of a sudden it's frustratingly hard to hit him. Not only does it eat up time, but he casts a wall of spells that you're almost guaranteed to hit on your way back down. And that's just in the vanilla game, good fucking luck if you're playing Coin Rush where you're starting off with a 100 second time limit in one of the longest stages in the game.
 * The closest thing to this in New Super Mario Bros is probably Monty Tank, the boss of world six. His Bullet Bills and Bob-ombs aren't overtly deadly, but in the last phase he becomes a bit tricky: The tank grows so high that you have to Goomba Springboard off a Bullet Bill to hit him. Which isn't easy without getting hurt, as he likes shooting two or three Bullet Bills directly above each other. Add the time trouble you get when you started the level from the beginning (it's one of the longest castles of the game), and you'll really get some challenge, especially when you're a One-Hit-Point Wonder.
 * Want to defeat Dry Bowser without taking damage? He's significantly faster than Bowser of World 1, and he'll barely give you enough time to run under him when he jumps. If you couldn't just run through him and take a hit, he would clearly qualify as That One Boss.
 * The Dual Boss fight against the Hisstocrats in Super Mario 3D World is a nightmare, which is a jarring change from how their separate boss fights normally are. Said Dual Boss fight is in the middle of World Flower's brutal Boss Rush, where you'll eat through a huge chunk of the surprisingly strict 500 second time limit just from fighting them. The best way to beat them in a timely manner is by hitting the other Hisstocrat immediately after stomping on the first, which is hard to do without having a storm of fireballs and several other bosses to worry about. If you don't, you're likely to die just shy of beating the level provided the other bosses or the Hisstocrats themselves don't do you in.
 * Super Mario Odyssey doesn't really have any hard boss fights while you're playing through the story. But once the postgame opens up, the initially easy bosses really start to bring their A-game.
 * Remember how Topper was the game's Warmup Boss and didn't get much stronger for the rematch at Bowser's Castle? Well, he kicks off the Broodal Boss Rush on where he's gotten so tough that he can single-handedly ruin your run. He's now packing a massive amount of hats that he can send spinning all across the floor at random. And since Cappy can only destroy one at a time, it's easy to be overwhelmed by the ruthless onslaught of hats. Fittingly, his massive amount of hats translate into a huge column when he slams them onto you, and unlike past fights you likely won't be able to escape the range of his super fast spinning attack, meaning that you'll have to ride out the storm with several precise jumps. Thankfully the other Broodal rematches aren't too tough, but if Topper doesn't defeat you outright, you'll likely be unable to take another hit. A scary prospect, when you have four other bosses and  to worry about.
 * Knucklotec doesn't change up his strategy, but he doesn't need to: his rematch has hordes of Chinchos constantly spawning and chasing after you. They're tricky, persistent, and hard to hit without damaging yourself. And when you aren't trying and failing to thin the herd between attacks on Knucklotec himself, they're corralling you directly into the path of his own attacks.
 * The is infamous for being a little too easy for being such an imposing, terrifying opponent. But his easily dodged electric buzzsaws and onslaught of ground-based lightning attacks are obnoxiously hard to dodge in the rematch thanks to his arena's icy floor. Not only is it slippery and hard to move around on, but you also take a speed penalty before you really get moving, which is a very bad thing when you're being assaulted by tons of electric attacks with very little room to dodge.
 * In Bowser's Fury, the first boss fight against Fury Bowser in the Ruins is a huge step up from the preceding fight thanks to one deadly new attack: he'll use his shell as a wheel and try to run Mario over, leaving trails of ink behind that will mess with your speed. He's fast as hell, and spends a lot of time offscreen which makes keeping track of him a real bitch to do, even with the cursor giving you a rough approximation of where he is. And if you try to hide from him on top of the various structures on Lake Lapcat's islands, he'll leap up towards you. In later fights, he'll always shoot a bunch of spikes that you can throw at him to instantly knock him out of wheel mode, but you get no such luxury here, and there's a very real risk of being comboed to death in seconds if you're having a real bad day.
 * The 100% version of the final battle is also really tough: not the Fury Bowser portion, but
 * The very first boss in Wario Land is one of these, being the hardest boss in the game. One hit makes attacking him nearly impossible, he's pretty quick in attacking and attacks from land, the ceiling and underground in various phases. Also a rather harsh "Wake-Up Call" Boss.
 * There's also Bloomsday/Scumflower in Wario Land Shake It, who is probably the one boss in the game who takes the longest to defeat (three different attack patterns), can cause earthquakes and hurricanes to mess you up, and has to be very slowly knocked backwards off the edge by throwing enemies and then quickly attacking him a few times.
 * In Wario World, my god, Red Brief J. Not only were his attack patterns extremely hard to avoid and dealt you even 5 hearts of damage in one hit, to add insult to injury it's a muscular bull in a speedo.
 * From Wario Land 4, you have Aerodent, a giant teddy bear balloon being piloted by a rat...thing. Aerodent floats overhead, throwing down Spikebutts, which you have to flip over and throw into a patch (with wonky collision detection) to deflate Aerodent. Then, when it drifts downward a bit, you hit the feet with Wario's barge attack to flip it over, then FINALLY you can hit the rat a couple times before it reinflates the bear and floats back up. And as you repeat this process, it throws down fireballs, which turn you into Fire Wario, which just wastes time. The only way to get a perfect score for this boss is to grind medals and get the Large Lips to take its health down to two hearts, and even then it's still a difficult fight.
 * The Sorcerer Fox in Wario Land 3, mostly because hitting him involves bouncing an enemy off the walls, and because his projectiles are extremely difficult to avoid on the last hit.
 * Ashley's boss microgame from WarioWare: Touched! features borderline Bullet Hell patterns of projectiles to dodge and an end boss that has three separate pieces shooting things at you.

Metroid

 * Ridley is the Metroid equivalent to Death from Castlevania - a recurring boss that always makes you want to hurl a controller. To make him even more like Death, when he turned out to be a pushover in Metroid: Zero Mission, fans complained. He WAS hard in Super Metroid, though. Part of what makes him stand out is that while all other bosses have weak points that you can target and fairly predictable attack patterns, there is no trick to fighting Ridley other than to drop his HP to 0 before he does the same to you, and he has a lot more HP and attack strength than you do. And then there are Self Imposed Challenges. Low percent runs or even sequence breaking for the hell of it makes him hard as you have to dodge all his attacks and try to replenish your supply of missles with a beam that only goes a few pixels.
 * Metroid Prime had a cruel bait-and-switch version of this. At first, it just seems like Ridley's gonna fly around, bombarding you with easily-dodgable lasers and missiles. Then, when you get his health down to a quarter, he goes No Winged Dragon and promptly chews you up.
 * The (aptly named) Nightmare in Metroid Fusion caused more than one Game Boy Advance to go through a wall. Aside from the huge amount of damage it does to you every hit, it also can inhibit your movement by manipulating gravity.
 * There's also the Security Robot. Both times you fight it, you have to hang from monkeybars on the ceiling and shoot down into its core, which is easier said than done. It can't be hit when it attacks, and its attacks are all designed to knock you off the ceiling to get trampled by the thing. Just to add to it, the second fight takes place above a pool of electrified water, which knocks your health off very quickly.
 * Yazuka the Kung-Fu Spider. Its first form zigzags across the boss room, trying to pick you up. If it does, it'll lift you up and slam you into the ground, taking off a huge chunk of HP in the process. It's only vulnerable at certain times (namely, when it spits fireballs). After you blast its legs off, it starts space-jumping around the room, spitting projectiles at you when it stops.
 * The final showdown with SA-X? It's a fight against an exact duplicate of your character that attacks relentlessly with all of your devastating special weapons -- except that it can take a lot more damage and has the superior dexterity of a computer. Winning this encounter comes out to learning how to screw with the AI.
 * Thardus and the Omega Pirate from Metroid Prime (although, arguably, Omega Pirate is not so much That One Boss as merely the cap to That One Dungeon (the Phazon Mines.)
 * Thardus is just dang huge, and thus its attacks hit like a train made of boulders. Most of the time it's throwing boulders at you or curling up and rolling around the room, where it's very hard to dodge because of its size. To damage it, you have to switch to the Thermal Visor, shoot out the highlighted boulder in its body, switch back to the normal visor, and continue blasting away at the highlighted boulder. You have to do this a lot. And as the fight goes on, it summons a snowstorm that makes it impossible to see more than 10 feet away, which makes it a whole lot harder to dodge its rolling. Annoying and long enough normally... Hard mode is a whole 'nother beast.
 * Omega Pirate is pretty easy on normal, if only because the fight is rather quick (you can kill him pretty easily in two rounds), so with enough energy tanks you should be able to survive longer than him. On hard mode, the fight takes a lot longer unless you're really quick with firing super missiles at him, making him quite possibly the hardest boss in game (or at least a very close contender to Meta Ridley) The Omega Pirate is especially infuriating on hard mode in that, while most enemies have double health and do double damage (making them about 4 times harder), the Omega Pirate takes twice as long to desroy his armor, which has to be done twice as often (due to the double health), and still does double damage, making it a whopping 8 times harder . And let's not forget that it can summon some of the toughest enemies in the game. The worst part is the mook rush he starts throwing at you. You'd better hope not too many of them are Wave Troopers, because they take freaking forever to kill and you get overwhelmed fast.
 * Meta. Fucking. Ridley. Curiously, some people found him a lot easier on hard mode. It might be just having more skill at the game. And if you get past that... have fun getting hung up on the big, bad Metroid Prime itself. This is especially true on hard, people can breeze through on their first try on normal only to get hung up on hard. Is she really that much harder? It's just exposing her weak point and doing barely any damage in barely any time.
 * From Metroid Prime 2: The Boost Guardian and Spider Ball Guardian both hold the position of That One Boss for different reasons.
 * The Spider Ball Guardian is a nasty, confusing Puzzle Boss. The battle is done entirely in Morph Ball mode and involves setting traps for the guardian. The problem is, several of the traps are nearly impossible to reach without minute precision. In addition, a design oversight makes the final area of the fight much more difficult than it should be; several of the Bomb Slots you need to activate are located at the top of slight rises, meaning it's very easy to overshoot the mark, wasting the small window of time you have to activate all three.
 * The Boost Guardian is just aggravating. The entire fight takes place on Dark Aether and involves steadily taking damage. The guardian is... zippy and will do a ton of damage if the player gets too close to it. The fight takes place in a tiny confined little room. Every so often, the Guardian will shift into a little sphere and rocket around for far too long, careening into Samus with alarming frequency and accuracy. It's completely up to luck however often he hits you. You can go the entire fight, not get hit once, and then get ripped apart when you've got him down to a quarter health. In addition, it's entirely possible to come out of the fight with too little health to get to a safe zone. It's unlikely, but there's nothing more soul-crushing than having to go through that fight twice.
 * An aggravating part of the Boost Guardian fight is that one of the best methods of health recovery is to trick it to destroy one of the pillars in the room for an easy 100 health item. Now imagine what happens when it uses its boost to destroy all four pillars in one salvo. At the start of the battle. When you don't need to regain 400 health. Hngh.
 * The Boost Guardian and Spider Ball Guardian are so infamous for being difficult that, when Metroid Prime 2 was ported to the Wii, they were the only two bosses who were made easier.
 * While typically not quite as difficult as the Boost Guardian or the Spider Guardian, the Power Bomb Guardian can be pretty damn frustrating. To beat the boss, the player needs to crawl up a maze of Spider Ball tracks to four activate different bomb slots. After activating one, Samus falls down and has to climb up again, and all the while the boss is shooting Power Bombs at you and Inglets are spawning everywhere shooting globs of darkness at the player, both of which will damage and cause Samus to fall. It is only possible to climb the rails in the Morph Ball, so any gamer will be defenseless against the Inglets unless he or she can coax them into the range of one of the boss's Power Bombs.
 * Not to mention that the Power Bomb Guardian will often throw power bombs in front of Samus' path, giving her only enough time to roll away before being hit. Forget trying to avoid them if you're on a small strip of magnetic rail.
 * And then there's Emperor Ing, though his infamy may be more due to his cheapness than his difficulty, particularly in his final form. On the other hand, you may have no problem with the 2nd stage and not be all to troubled by the 3rd stage (depends on how much the other two destroyed you). Only to find the 1st stage to be the very definition of this trope.
 * Chykka, which goes from "alright" to "JUST DIE ALREADY", is an irritating, long boss. The first phase is easy enough, but then it goes downhill fast. The strategy for the adult form sounds simple at first- "stun it and shoot the wings from behind"- but turns into an exercise in patience. The thing darts around to the point where the only way to even have a chance to hit it is to spam normal shots, since the shots are pathetically slow. If that sounds hard enough, there's still some attacks that are tough to dodge. Once the thing finally goes dow- just kidding, it still has most of its health. As it goes down, it releases a huge water wave that is almost impossible to dodge without jumping well in advance. Then it comes up as Dark Chykka. Welcome to the longest boss fight until the final boss in the game. Oddly, this phase is easier than before, since it doesn't dart around at all and the best strategy is to shoot its inflated eggsac with charged Light Beam shots. Even after it comes back up as normal Chykka, it still has half of its life left. It gains new attacks, especially where it flies around, almost impossible to hit. Repeat again, and the thing finally dies. Let's face it, Torvus Bog is full of Those Bosses.
 * Alpha Blogg. It's near impossible to avoid its ramming to make it open its damn mouth, which is how you damage it. If it hits you, it takes away 30 health on normal (and about 50 on hard), making your energy tanks drain fast. Even then, its mouth opens later and later when it rams, requiring split second dodging.
 * Don't forget the Grapple Guardian, which isn't so much hard as just aggravating to hit at all. First you need to target its eye and damage it until the boss gets enraged. The eye is rather small, but mercifully is easy to hit. Expect to either spam your basic power beam until your finger hurts or waste your precious light/dark ammo, however. Once you hit it enough, the Grapple Guardian fires the eponymous Grapple Beam at you. If you get hit, you'll take damage as you get closer and closer to it. If it misses completely, you're soon back to the eye phase, during which it takes no "real" HP damage. The trick is to stand behind one of the electrified pillars in the room and let the boss stun itself by grappling it. Once it does you can hit its back, but by the time you've run/jumped behind it you only have a second to act. Firing a Super Missile (as you will want to do) takes almost precisely this amount of time. A 5-shot spread missile is a bit faster, but takes time to lock on instead. Charged beam shots also work, but either drain a lot of ammo or leave you with very little damage dealt. It should be noted that the boss actually gets easier when it Turns Red later, since the process for hurting it becomes a lot quicker.
 * Metroid Prime 3 has Gandrayda. The first half of the battle is easy, the third quarter is more challenging but still okay but the last quarter is extremely difficult to hit and pretty much alternates between invisible (which requires you to change visor) and hypermode (which jams the visor and forces you to go hypermode yourself to damage the boss, which can become a problem if your health is already getting low).
 * Special mention goes to Mogenar, which becomes a long ordeal on higher difficulties. His weakpoints are protected by spheres that he can recharge, and on the highest difficult, they are very hard to destroy, the recharge is nearly impossible to prevent completely, and you'll likely need to destroy each sphere at least twice before you can destroy the weakpoint underneath. And he has 4 of them. And the last one is on his back, so pretty much the only way to get to it is to make him charge into a wall and dump a Hyper tank into him while he's looking around. Not that you have any energy to spare, natch - 4 tanks, maybe 5 tops, is about all you can have at that point in the game, and you can't go hyper without having at least one full. That said, with a little practice Mogenar gets easy... except for the part where you have to bomb his damn shoes off. This requires you to get into morph ball form after jumping over a shockwave, but before he manages to step on you, then planting perfectly timed bombs.
 * Dark Samus is a fairly tough final opponent on Normal. On Hypermode? She's unabashedly sadistic. It mostly has to do with the health system you use during the battle, which essentially acts as a combo timer/hit counter, but her attacks are still a pain to dodge and she loves to spam them. And if by some chance you get to, it becomes nigh impossible. We're talking four different attacks, and they all take a major chunk out of your remaining energy. At least Dark Samus gave you health pickups...
 * The Slench in Metroid Prime: Hunters. Not only are they hard as snot to hit when their giant eyes start flying around, but killing all of their "life support tubes" in order to damage them in the first place is frequently an ordeal in and of itself. The worst thing of all that the eye is moving so fast, and only the center will take damage, and you don't have any targeting system to lock on it. After defeating it its advisable to take a long rest. (To make matters worse you have a timer after each boss battle... at least it creates a checkpoint after you defeat the boss so you're not forced to kill it again.
 * Every playthrough of Zero Mission can be a massive hold up on that stupid Zero Suit Chozo boss. The first 3 hits are fine, but the last is nigh impossible to hit due to lack of time frame, and if you're too late it'll hit you instead (that's what it does whenever it doesn't flash vulnerable and it just gets annoying after a while). Let's have a little clarification. Near the end of the game, you fight one of the last remaining Chozo artifacts. To defeat it, you need to shoot it four times when it's vulnerable. At any time when it's not vulnerable, it will show mirrored image of Samus, and shooting it will cause her to take damage instead. Sound's simple, right? Don't get used to it. Once you've lowered its health a bit, it will float around the room in increasingly erratic patterns, hoping to do you in via Collision Damage. It also drops lightning bolts that crawl across the floor and ceiling. So, the final score? It flies around randomly, it hurts to shoot it sometimes, and it makes the environment you face it in lethal. Have fun!
 * On Hard, the difficulty spikes considerably: the boss itself and its movements don't change, but because Hard Mode halves the total amount of energy you can pick up (energy tanks now only give you half a full unit apiece) and raises the damage that enemies do, you have a maximum of four and a half full tanks at this point in the game and the boss now does a full energy tank with every hit. Luck will be a factor in your success.
 * As you're facing it down, the in Other M will spawn a normal Metroid; the only way to kill said Metroid is to shoot it with a charge shot to freeze it, and then aim at it (pointing the Wii remote at the screen and being locked into a stationary first-person perspective) while you charge up and fire a super missile at it. Not a problem until the she starts hemorrhaging so many Metroids that it becomes literally impossible to freeze some Metroids and charge up a super missile without getting snagged by other Metroids, unless you freeze ALL of them before the first one you froze in the sequence wakes up. There's no special tactic, just using sense-move at the last second, firing at the clusters and hoping to god your energy doesn't get too low, because if it does, you're fucked, considering you won't have time in this battle to use Concentration before a Metroid head-rapes you. Then in the second phase, it tosses out heavy-hitting attacks that are almost impossible to dodge. And then the third phase makes you use a technique that you haven't been allowed to use (and don't even know you can use) since the opening tutorial eight hours previous, within five seconds or you die. Joy.
 * There's the Rhedogian (that flying anomalocaris thing), which you have to fight four times. He's really freakin' fast, dodges nearly anything, does heavy damage, has hard-to-dodge attacks, and is invincible most of the time. Also, the first two times you fight it, you have barely any room to maneuver around, and the second time you can get a Nonstandard Game Over if you take too long (read: don't know what to do) before getting to him. Thankfully, after the third time around you get the Screw Attack, which makes him significantly easier.
 * Arguably Goyagma, in a "Wake-Up Call" Boss sense. Faced just after a hellish sequence without the Varia suit, Goyagma is easy enough to hit and damage, but his attacks are very unpredictable. He has long arms which he slices across the platform you're on. Sometimes, he'll do it twice. Unfortunately, it can be very hard to tell when to jump as sometimes he swipes slow and sometimes fast, with little to no indication and so you may jump too early or too late. Later in the battle, one of his attacks is a constant hand smash to avoid - but it also forms a mini-eruption where you're at, so you have to get ready to dodge that quickly too. Near the very end, he will do the mini-eruption thing, THEN very quickly follow up with a fast swipe. You won't see it coming. In Hard mode, each of these attacks do 1/3 damage. So that's 1/3 for each mistake, and it's hard to predict against.

Sonic The Hedgehog

 * The original Sonic the Hedgehog has the Labyrinth Zone boss, where Eggman simply flies up through a vertical passageway and you have to give chase. If you're savvy, then yes, it's as deceptively easy as it sounds. It's a tight corridor jam-packed with spear traps, fire hazards, and constantly filling up with water to slow you down. Should the rising water overtake you, there are no stops anywhere to replenish air. One false move, and you're as good as dead - and God help you if you die and have to try again without a single ring.
 * Its sequel, Sonic the Hedgehog 2, has the Death Egg's back-to-back boss fights: First you have to beat Sonic's doppelganger, Silver Sonic, without any rings to spare. The Death Egg Robot follows right after, and defeating him requires absolutely precise timing (which is even tougher when playing as Knuckles due to his jump height), dodging very fast attacks, and if you get stuck behind him, consider yourself boned as you likely will have no room to avoid the subsequent shower of explosives. One single hit will send you right back to Silver Sonic, which only adds to the aggravation.
 * For Sonic 3 and Knuckles, who That One Boss is depends mostly on which character you're playing as:
 * For Sonic, there's the Carnival Night Zone Act 2 boss. Robotnik drops a big green ball, does a lame attack that takes forever, then comes down to pick up the ball, the only window of opportunity to hit him before waiting all over again. It's a very time-consuming boss, right after what's also arguably the longest act in the game, leading to a lot of deaths when players ran out of time.
 * When playing solo as Tails, Marble Garden Zone's second act boss is incredibly tough: Unlike Sonic's version, where Tails is carrying Sonic through the air while you hurl Sonic at Eggman's flying robot, Sonic himself is a no-show, meaning the only way for Tails to damage the boss is to ram at it from underneath with his propeller butt. 50% of Robotnik's movement patterns make this a tall order to say the least.
 * For Knuckles, the already aggravating Ice Cap Zone second act boss becomes merciless: As it is, the boss sprays instantly freezing gas all over itself, and it's really hard to predict his patterns, which Knuckles' short jump height certainly doesn't help. But the worst part is that the platform you have to use to reach the boss isn't only under constant freeze gas, but it actually lifts up and down every second, meaning the timing of your attack must be dead on or you will be hit. And during his kamikaze run, Knuckles can't jump over it, so you'll have to land the two last blows fast enough or be killed.
 * The antlion boss of Underground Zone, from the 8-bit version of Sonic 2, is almost more infamous than the game itself. You can't damage it on your own, you can only win by dodging the barrage of boulders that come bouncing downhill from the other side of the screen. And since you don't get any rings, failing to dodge even one hit kills you. Did I mention that this is just the first boss?
 * If that just doesn't sound enough "That One Boss"-ish for you, it seems the people who made the game agreed - it was made for the Master System first, then ported to the Game Gear. In the transition, they made the boulders able to bounce downhill at three different speeds selected at random. Yes, that's right - they made it harder on the version with the smaller screen area to see shit in!
 * Another Game Gear boss is the frikkin' Jungle Zone boss of Sonic 1. None of the bosses allow you to have rings as it is, but basically you're on a tiny rope thing while Eggman is above you firing cannon balls down, which roll on the rope. You can only hit him with enough height from the edges, but try not to fall into the abyss. Frustratingly, it's quite easy to mistime your jump to the capsule afterwards, and fall into the pit after having beaten him.
 * The final Tails vs. Eggman fight in Sonic Adventure 2. Regardless of which one you're playing as, your opponent at various stages of their health will attack with their super attacks from the game's Vs. Mode that you can't use regardless of who you're playing as, including the dreaded Power Laser, which is RIDICULOUSLY hard to dodge as your opponent is constantly turning in your direction while firing it. To top it all off, it's extremely hard to hit them with your missiles, you're much better off just using your standard pea shooter to get in hits; but since your pea shooter and homing missiles are tied to the same button, there's a chance you'll hit the respawning floating green canister in the middle of the arena, which will likely do a ton of damage to you due to being in close proximity of it thanks to chasing your opponent everywhere.
 * Or, another way to sum up the aforementioned battle is this: if you do not make your opponent fall to his knees in about 20 seconds or so, you can probably kiss your ass goodbye.
 * How about the final fight against Shadow/Sonic? After a few easy hits, they'll jump in the air and dodge almost every hit you try to strike them with. The only way to hit them is to spin dash into them the split second when they teleport in front of you (which, again, is a power only the AI comprehends). Ironically it's very easy to just bum rush your opponent if you get them to use their Vs. mode special attack (Sonic Wind/Chaos Spear), but to do this you have to deliberately slow down to provoke them into stopping to fire it.
 * The Biolizard. It's pretty grueling to fight as it is, but particularly in regard to trying to get the final hit. Basically: Shadow is stuck floating in mid-air in some weird bouncy wave pattern, having to go side to side dodging floating eggs that are individually launched and each trying to hit you (and since you cannot recover rings in mid-air, this means you can only take two hits at most before instant death, which brings you back to the beginning of this long slog), all while attempting to get into the very center of those killer floating eggs to pull off a perfectly timed press of the A button. Too close? Take damage. Too far? Doesn't work.
 * Egg Viper from Sonic Adventure, about the only boss in that game to usually present a problem. Toward the end of the fight, Eggman begins destroying sections of your only remaining foothold. That itself is motivation to hurry up, but when you "defeat" the Viper, Eggman goes kamikaze and attempts to drag you down into a very deep hole by crashing into the foothold. Should you have more than one section of platform to stand on by then, just dodge to the side. Should you have nothing to dodge to the side to, well... try harder next time!
 * An example from Sonic Rush Adventure: The Ghost Titan. The story mode version is almost as bad, but when you're Sol Emerald hunting in mission mode, the difficulty is ramped up to insane proportions. Ghost Titan has a hefty amount of attacks under its belt, and it can use several of them simultaneously. Many of its attacks are very, very hard to dodge. The most efficient way to damage it is to launch yourself into a cannon and shoot yourself at it, and you must first do this by having the boss attack the cannon's electric barrier enough times (while not getting rammed yourself). Then, you must attack the cannon enough times as it constantly fires across the field. As though that weren't painful enough, dropped rings behave rather strangely in this game: the more you get hit, the farther your rings fly. Get hit enough times and your rings will fly off the screen, rendering it impossible to pick them back up. You can't really conserve on-field rings since all the running and jumping around forces you to collect them, not to mention there are rings high above that you can only reach during a descent after launching yourself in a cannon.
 * The Egg Frog in Sonic Advance Trilogy 2, due to the fact that it's very fast and it can jump on the ceiling which make hitting it even harder without taking damage. Think of Gravity Man's boss fight in Mega Man 5, but while you're constantly running at Sonic the Hedgehog level speed.
 * Advance 2's Egg Saucer has got to be a major contender for poster child of this trope. It's equipped with a laser gun that can be very hard to dodge at times, and a metal fist that can smack at you from a distance. You can destroy the gun, but that also makes the fist (which, naturally, is invincible) become faster and even harder to dodge. Because of these two weapons and the constant spinning motion of the machine, the window of opportunity to hit Eggman is very small. Now then, for the punchline: if you destroy the laser and are pinned against the floor by the pissed-off hand's long-range whirling attack, you will die instantly, rings or no rings. Run out of lives against this cheap monstrosity, and it's back to Act 1 of an already long and frustrating zone. Fun!
 * Sonic CD, Stardust Speedway. You're racing Metal Sonic, from start to finish (loser dies, of course), with several spikes in your path, and sections that hamper your speed if stumbled into. Metal Sonic can just plow through the spikes like nobody's business, and if you're ahead of him, he'll create a barrier around himself, and rush forward with breakneck speed, running through you and causing you to lose all your momentum if you aren't paying attention. If he's ahead of you, then his movements slow to a crawl, but he also generates lightning around himself, which will also hurt you. Meanwhile, Robotnik is trailing behind you with a laser coming from his craft; if you fall too far behind and touch the laser, you die on the spot. No pressure or anything!
 * Sonic Advance 3. As opposed to the bosses you can actually hit, the Twinkle Snow Zone boss, Egg Chase, takes a bit of intuition. Its a climbing platform with a wrecking ball that shoots out at you. You can't hit it directly, but you can land on platforms and jump off to make them drop, which will hopefully fall on him to inflict damage. The problem is, if the wrecking ball should intercept you as you're jumping towards a platform, you will fall off the bottom and die, unless you can very quickly switch to flight. Of course, that requires a team where the lead character can fly on their own. That doesn't happen very often...
 * The first Sonic Advance had the boss of Ice Mountain Zone. Robotnik pilots a drill machine which drills the cieling to make stalactites fall, which you have to ascend to be able to reach him. Trouble is, you're fighting him underwater. And in this game, it doesn't take as long to drown as it did in previous titles, and your movement is significantly slowed down.
 * Amy, hilariously, makes mincemeat of the above boss. From the floor level she can simply jump and swing her hammer to hit Eggman from below, and can just do a Hammer Jump to poke her head above water enough to avoid drowning.
 * The final boss of Sonic Unleashed will cause a ceaseless stream of profanities for anyone unfamiliar with it. A rundown of the Wii/PS2 version:
 * The first phase will kick your ass if
 * The last phase (with Super Sonic) can be brutal-- rings can sometimes be hard to find, the game gives little to no indication as to how to lock on to an eye (and once you do, you have lots of meteors to contend with), and 's attacks can be hard to avoid even if you know where it's going to hit.
 * The PS3/360 version of the fight takes the frustration past eleven and possibly to twenty.
 * For half the time in the final phase, you must fly over to the boss as, while dodging fireballs, and complete a series of QTE's to proceed. After throwing a series of giant fireballs (which are hard to avoid thanks to sluggish controls), the boss will unleash an unavoidable beam which, if you didn't hit "guard" in time, will take a significant chunk of your health away. In other words, this is a Damage Sponge Boss in reverse. For the first two runs, they're manageable; for the third and final flythrough, good luck resisting the urge to throw your controller out the window.
 * The other half of the time, you must run through as Sonic to the end of a tricky obstacle course and complete a small sequence of QTE's, as in the WiiS2 version. Unlike the PSWii version, however, you are timed. If you don't make it to the end in time, you die have to start over from the beginning of the section.
 * The final phase of the battle requires you, as Super Sonic, to destroy seven barrier-emitting tentacles of Though Super Sonic has a health bar,  has one as well, and it serves as a timer constantly ticking down to failure and a restart. After the shield's destroyed, you must defeat the boss with a very long sequence of QTE's, the last of which requires you to mash the X button 60 times in 10 seconds. This is not an exaggeration.
 * If you happen to run out of lives anywhere in the above sequence and get a Game Over, you have to go back and re-fight Egg Dragoon, an easy but tedious boss, before you can reach the final boss again. Assuming your will to live isn't completely broken by now, that is!
 * Fighting Silver as Sonic in |Sonic the Hedgehog 2006 is (shockingly) a nightmare. You don't have much room to maneuver, the camera is completely unhelpful and leaves you to fend for yourself, the only time Silver's vulnerable is when he's about to throw something at you, and if he grabs you with his telekinesis, you're going to die and no amount of rings can save you. This is because he'll throw you a second time as you're reeling from the first attack - Mercy Invincibility doesn't work. Especially brutal if you go into this battle for the first time, not knowing what to expect; you take one step forward and all of a sudden, you're thrown into the air and killed. He collapses in roughly four hits, if you can actually get the chance to do so.
 * It's possibly unintentional, but in Silver's version of the battle, Sonic is laughably easy to beat.
 * Egg Breaker from Shadow the Hedgehog pops up in three different places over the story and is predictably pathetic two of those times (the Iron Jungle battle can even be easily won in about 7 seconds). The Mad Matrix rematch, though is nothing to sneeze at - the mook bots you're supposed to get ammo from are flooding the stage with rocket launcher explosions, and backing away from Eggman to avoid his melee attacks provokes him into spamming an obnoxious meme that fires giant projectiles across the stage in every direction. Constantly.
 * The final boss from Sonic the Hedgehog 4: Episode 1. Think of a redone version of Sonic 2's final boss, but with 2 phases, and with much more hit points. (8 hits? Heck no). His second phase is barely open to attack. And finally, after you think it's all over, he tries to pull an Egg Viper. If you get caught in this, you'll have to redo the fight from the start. It doesn't help either that one of the achievements means defeating all 5 bosses in this final stage without being hit once.
 * Sonic Generations has two bosses: The Egg Dragoon and the Time Eater.
 * The Egg Dragoon is a Modern Eggman invention capable of matching or beating Sonic's top running speed. It is armed with several weapons, including freeze and heat rays, homing missiles whose explosions can still hurt you after you dodged them, plus in a 2D shift, a crushing attack you have to wall jump up while dodging freezing shots to do a homing attack on Eggman. As if this wasn't bad enough, damage him enough he'll start launching several of these attack simultaneously, making it very difficult to get through unscathed. There is one phase where you are falling and must boost your way down while dodging missiles.
 * The Time Eater, on the other hand, has only two attacks, neither of which are very effective. The trouble is even with Super Sonic boosting it can be very hard to hit this boss the four times required to defeat it. There's lots of debris and the Sonic you send ahead to blast away the debris isn't very accurate. On top of this rings become very hard to see in time and while boosting can draw rings your way, it's a matter of timing and proximity. In short, by the time you get the third hit in, you might be seriously hurting for enough rings to sustain you for the "sure" final blow against the boss.
 * Out of the many mysterious robots you're pitted against in Sonic Frontiers, a select few will definitely put your through the wringer.
 * Patrolling the skies of Kronos and Chaos Island are Squids, which are ridiculously annoying despite being minibosses. If you even want to fight them you have to wait for them to fly low enough at one of few select locations so you can hop onto the deteriorating digital trail that they leave behind. And as far as the actual fight itself goes, it's a frustrating and tedious slog where you have to constantly dodge salvos of bullets while you slowly close the distance between you and the Squid. Sometimes, the Squid's in view and you can easily dodge them. But more often than not, the camera angle hides the Squid and its bullets meaning that you won't know where to dodge until it's too late. And even when the camera isn't screwing you over, getting close to the Squid is also dangerous because its bullets come out fast and are hard to react to outside of jumping and praying that you made the right call.
 * And if that wasn't awful enough, they also throw in some Goddamned Boss traits into the mix, such as taking forever to kill on the best of days, and having a massive aggro radius that requires you to run far from it if you want to disengage from combat despite not being in any danger as long as you aren't actively chasing it. This can make interacting with NPC's like Amy, Tails, or Sage way more annoying than it has to be, since you can't talk with them while a Squid has aggroed.
 * The Striders from Ares Island can't be hurt unless you form three complete circles on a series of grind rails near their core. While this isn't hard to do the first time, doing it a second time is pure hell. While you've already had to deal with it firing lasers that travel around the rails, it now fires homing lasers that actively chase you down and change lanes so they can catch you. It's so infuriatingly easy to get hit, and while you can disengage and grab more rings if you run out, you can easily lose them all over again due to how aggressive those lasers are. Unless you've leveled up your attack a bunch (and unlocked your stronger attacks), it's best to give these guys a wide berth unless you know you can kill them as soon as they're vulnerable.
 * While their difficulty is to be expected since you find them on the last island in the game, the Caterpillar minibosses on Ouranos Island are still a pain, and not for the right reasons. Like with the Striders, you have to make them vulnerable by riding around on rails, this time collecting blue orbs while avoiding pink and yellow ones which hurt you. Again, the first time is easy, but if you're forced to do it a second time, the Caterpillar wises up and floods the rails with projectiles. And unlike the Striders, you can't disengage and gather more rings. If your ring count has hit zero, your only options are to brave the projectile storm and grab the spheres or die.
 * Like any minibosses you can kill Caterpillars before "round 2" begins, but they don't make it easy for you. You have to attack the tiny weakpoint on their backs, which has wonky hit detection, while dodging the crazy barrages of lasers these things fire at you. While not all minibosses are helpless when they're vulnerable, none of them are as dangerous as these guys.
 * The Wyvern, Ares Island's Titan Boss, is as amazing of a spectacle as the other Titan fights, but it's also a headache in the literal and metaphorical sense. Before you fight it you have to spend a lot of time chasing it down by climbing an obstacle course that's easy to fall off, climbing an equally annoying tower after that, and running down a trail similar to those employed by Squids right after that. And once you can finally fight the dumb thing, you're thrust into a fight against a foe who floods the screen with missiles (and laser rings in the second phase) that are awkward to safely dodge and will leave players that are prone to motion-sickness feeling nauseous. And unlike the previous Titan, Giganto, you can't freely beat it up: you have to parry its physical attacks to stun it first. And its attacks are so damn awkward to parry because they come out fast and are hard to read, and unlike most enemies and bosses it isn't enough to hold the parry buttons and call it a day: you have to actively parry them as they come out. Fail, and you have to dodge even more projectiles while your rings slowly drain, which will kill you if the count reaches zero. And should you die, you have to do everything from the beginning, climbing included.

The Legend Of Zelda

 * The Legend of Zelda:
 * Gleeok is a hydra monster found as a boss in levels 4, 6, and 8. It's a fire-spitting beast whose projectiles can't be blocked, and it's only vulnerable to the sword and the Magical Rod - as it sustains damage, its heads will also detach to fly around and attack, and it keeps getting more heads with every subsequent encounter (it's first encountered with two heads, then three, then four). Gleeok makes the other bosses look like pushovers, and if you're not good at sticking and dodging, then you best hope you have a potion left.
 * Manhandla, a four-headed plant-like monster is the boss of the third dungeon. At a point where you would normally have five or six heart containers, each hit from them takes off one full heart container. Its constant fire balls and its speed increasing with the removal of each head means it will be a very annoying fight if you don't manage to kill all four heads with one bomb. The later ones aren't quite so bad as you should have a new sword and more hearts by then.
 * If you play the game as intended, Ganon is a joke. But when you're doing a three heart and/or minimalist run, one of the game's easiest bosses suddenly becomes a lot more worthy of his Final Boss status. His annoying tendency to Tele Frag you is scary when you only have three hearts to your name, and if you only have the starting tunic it's a guaranteed One-Hit Kill. Even if you get lucky enough to not have him crash right into you, there's still his barrage of fireballs to watch out for.
 * Dark Link in Zelda II: The Adventure of Link. He will block nearly every single one of your attacks, and manage to punish every single mistake you make. Not only that, he likes to jump on you and do Collision Damage even though you can't do the same to him. The final nail in the coffin is that he's right after another tough boss, and there is no fairy or healing of any kind between the two, unless you have enough magic (Which is unlikely, seeing how the costly Thunder magic is the only thing that can damage the previous boss). Finally, lose all your lives, and it's back to the beginning of the Great Palace. The fight can be rendered a non-issue by exploiting his AI, but good luck figuring that out as a kid in the 80s.
 * The boss fought directly before him, Thunderbird, is just as bad. In fact, he's even worse due to lacking an AI exploit! You'll have to sacrifice a huge chunk of magic by casting a thunder spell just to hurt him, and the rest of the fight has him rain down a hail of fireballs on you while you try and fail to stab him in his tiny little face while he flies all over the arena.
 * Encountered far earlier than these two is Reboknack, who starts off easy when you fight him on horseback. But once you deal enough damage, the horse dies and he fights you on foot, which is basically like fighting a Blue Darknut with a health bar, complete with sword beam spam and an annoying tendency to block a good 90% of your attacks.
 * The Legend of Zelda: A Link to the Past:
 * Moldorm should definitely qualify - not because he has any scary or devastating attacks. No no no, he'll just knock you off the platform by ramming into you, which restarts the battle and returns him to full health. Meanwhile, you have to hit his tiny tail, which he can actually cover with his oversized head. And you don't want to hit his head, because hitting it will send you flying, likely right off the platform thanks to the truly ridiculous knockback from slashing at the wrong body part. And this is if you're having a good day: his movements are very difficult to predict, meaning that he's very likely to crash right into you for a whole heart's worth of damage. And on those days, expect to burn through most, if not all the hearts stocked outside of his boss room. If he's uncooperative, expect to have to do his fight over and over and over... and unlike Mothula, there's really nothing you can use except your sword on this guy.
 * Speedrunners in particular can get jerked around real bad if they're unlucky, because Moldorm's aggravating knockback and AI are what can make or break a Link to the Past speedrun.
 * Fought at the end of the first Dark World dungeon, the Helmasaur King makes for one hell of a welcome wagon. He's a lot more mobile than you'd expect a huge dinosaur monster like him to be, which makes breaking his helmet with your dinky little hammer tedious and frustrating. Meanwhile, you're trying your best not to get skewered by his mile-long stinger tail as it strikes you from weird angles, and once you break his helmet he starts belching up fireballs that break off into a wide-reaching scattershot.
 * Mothula holds the title of being the worst in this game. Erratic movement, randomly-changing conveyor floor, randomly moving blade traps, and a three-beam attack that's hard to avoid while you're dealing with all the other perils. Worse still, a bug in the original SNES versions made him invulnerable to certain attacks of the level 3 sword and almost all attacks of the level 4 sword (The weak poke is all that works). You can fall back on the Fire Rod, but that's only if you've got a full bar of magic to use it with. If you don't, then tough luck.
 * Trinexx. You have to use magic attacks to defeat him, which is made a little more merciful by the fact that magic potions are generated in the battle, but still very hard. The worst part, however, is the freaking middle head that bobs out at you fairly often. This will be your downfall in the fight. He gives warning as to when he's going to do it, but even so, it's very difficult to dodge.
 * Head Thwomp from The Legend of Zelda: Oracle of Ages is a case study in why you should never, ever, ever design a boss around a game of roulette. You feed him a bomb as he cycles through four different faces, and you have to hope and pray that they stop on red: if the bomb explodes on any other color, he'll launch one of three annoying attacks as punishment for getting a bad roll. Sometimes he'll even attack while you're preparing to chuck a bomb at him. And keep in mind, this guy is the second boss, so you're not going to have that many hearts when you face him. All you can really do is hope that RNGesus is on your side today.
 * The Legend of Zelda: Oracle of Seasons features the return of Gleeok, but he wasn't the only one that could try your patience. Digdogger is another returning boss that was made much more irritating to fight - you must the Magnetic Gloves to pull a spiked ball into it and towards you, and yes, it will hurt you if you don't let go in time. Manhandla also returns, resembling a four-headed Piranha Plant, and must be fought with the Magic Boomerang, the most frustrating item ever devised for this series.
 * Blaino from The Legend of Zelda: Link's Awakening is worse than Moldorm, for a single charged punch from him will punch you back to the dungeon entrance. He's also almost impossible to hit except when he's preparing a charged punch (which only takes a couple of seconds to charge); if you don't stand in quite the right place while attacking him, he'll hit you and start the battle over. And he has a quicker punch that stuns you, allowing him to land a dungeon-exit punch on you easily. By the way, this guy is the miniboss.
 * The Legend of Zelda: Ocarina of Time:
 * Dark Link is a good indication of when the game's done playing around. It's even more frustrating because he's only a miniboss. This is even worse considering that the actual boss of that level (a Scrappy Level through and through) is almost insultingly easy. Oh, and if you were hoping to use the Megaton Hammer or Din's Fire on him, they fixed that, so to speak, in Master Quest. You more or less have to beat him in a straight swordfight. A difficult duel could be fun, if there was some technique to it. But your quick-stab is useless (Dark Link jumps on top of your swords, then hits you), your jump attack is useless (Dark link jumps to the side, then jump-attacks you), and he seems to dodge the spin attack, which leaves madly mashing the standard attack, which Dark link seems to do endlessly with the same speed while locked on, so the blows deflect each other.
 * While Morpha can be easy if you fight it while hanging out near the walls, fighting as intended on the four platforms in the center of its room makes it easily one of the hardest bosses in the game. Its AI is obviously meant to take advantage of fighting you there, because the amoeba's snakelike body will swim around you and attack from unexpected angles, and every hit you take is painful because you slowly lose a good chunk of your health as it squeezes the life out of you before flinging you across the room. And when the nucleus separates itself from the main body, it's hard to yank it ashore and whack it because of how slippery and zippy the little guy is.
 * Just seeing Bongo Bongo requires you to use the Lens of Truth, which constantly drains magic. That alone isn't a good sign, and the boss fight itself will really put you through the wringer. If you don't want him to constantly bounce you around by drumming on the giant bongo you fight him on, you need to wear the slippery and unwieldly Hover Boots. And to actually hurt him, you have to stun his gigantic hands which will try to knock you off the drum and onto a floor that constantly damages you, and then shoot him before he can slam you with a hard-hitting tackle. It's surprisingly easy to miss your shot, and even Z-targeting can result in you completely missing the mark and getting run over by this thing. Thanks, Navi!
 * The Iron Knuckles from the Spirit Temple may be minibosses, but they're a lot scarier than most of the proper bosses. They start slow, but hit ridiculously hard (four hearts, specifically), and their axe swings come out incredibly fast. And once you deal enough damage, parts of their armor fall off, and all of a sudden, this huge, tanky Mighty Glacier becomes a Lightning Bruiser capable of keeping pace with a fleeing Link, and they swing their axes even faster. One is bad enough, so try not to cry when you're pitted against two at the same time.
 * The Legend of Zelda: Majora's Mask:
 * This game follows the pattern of the last, easily providing the Scrappy Level (Great Bay Temple) with the hardest boss in the game bar none (Gyorg). This fish from hell has to be shot with arrows or hit with Zora Link's boomerangs before you can properly hurt him. Then, you've got to dive into his pool of water and charge right into him with Zora Link's electric shield. Now you've got to escape the pool and begin the cycle all over again, which is a lot harder than it sounds because you're barely faster than Gyorg, and if he catches you he eats you before spitting you out for a ton of damage. Then after you've hurt him enough, he summons a school of little piranha minions to help patrol his turf.
 * The same temple also has easily the most difficult miniboss in Wart, a giant moving eyeball that had over 40 smaller eyes surrounding it. Those smaller eyes take two hits (one hit with the Gilded Sword) to destroy and after the first, they bounce around making the hookshot useless. And if you ignore the small eyes, after enough hits they all fall off and start bouncing around making the fight damn near impossible.
 * Gekko and Mad Jelly, who are also from the exact same temple. They're easier than Wart, but that's a small comfort since they're still really frustrating. Gekko will envelop himself in the Mad Jelly and cling to the ceiling, and you're supposed to shoot him down by nailing the Mad Jelly with an Ice Arrow. Miss, and it's nearly impossible to avoid the massive blob of jelly when it comes crashing down on you, and you slowly lose an entire heart's worth of health while Gekko beats the crap out of you. Hit it, and you have to dodge all the falling blobs Mad Jelly splits into while trying to hurt Gekko before he can run to safety.
 * Fighting Goht, which is a combination of Chasing Your Tail and dodging as many hazards as possible, can get annoying. Goht is also annoying in that you need to defeat him more times than the other boss for the 100% completion - the only perk is that by the fifth time around, you forget why he was so hard the first time. While some people find it very easy to avoid taking damage, the fight takes much longer that way.
 * The Legend of Zelda: The Wind Waker:
 * Gohdan can be this - after all, he is the guardian of the Tower of the Gods. Or he can also be very easy, beatable by a kid with just enough discipline to shoot at the right time.
 * Molgera. You have to get up really close to grab his tongue with the hookshot, but get even an inch closer than you need to and he'll eat you. It's nearly impossible to L-target the tongue after the first time, because mini-Molgeras spawn and get in the way, and it's even harder to target it manually because they'll hit you and interrupt your careful hookshot maneuvering.
 * Puppet Ganon, since he has three phases, each with its own attack pattern! Especially with the fast third form, an Expy of Moldorm from A Link to the Past, where you have to hit its tail with magic-depleting Light Arrows without the luxury of L-targeting. Shoot a Light Arrow at the blue ball? Fine. Shoot a Light Arrow at the blue ball on the tail of a fast-moving snake that goes all over the place and never holds still? I'd rather shoot the guy who designed that phase. Performing an attack at Puppet Ganon's head immobilizes it, but you'll need quick fingers to exploit the narrow gap of opportunity. Those who are patient can jam themselves onto a ledge in the room where Moldorm Ganon can't often can't touch Link. The trade-off is the tail becomes more difficult to hit. However, if you throw some all-purpose bait into the water of the arena during the Moldorm phase, it'll actually be attracted to it, which makes hitting its tail that much easier! Too bad there's absolutely no reason for a new player to even consider trying that.
 * The second battle with Phantom Ganon can last forever (literally) if the player doesn't figure out the riddle that holds the key to his defeat. Even finding the boss can be a bit tricky, since it requires the player to do something that completely defies previous game logic -
 * The Legend of Zelda: Twilight Princess:
 * Twilit Bloat, aka the Giant Lightning Bug From Nowhere. You have to fight it on a ring of small platforms, it has a charge attack, and you have to jump on it and bite it to death. If you miss, it gets a free hit. Also, you're essentially helpless in the water, and when it does its rampage attack, the only way to be safe is if you have the agility of a cat on speed. The boss is especially hard if you don't realize you have to use the force field to target and hit all the legs at once.
 * You can fight through the entire game and only have problems with one boss. Said boss was a miniboss, not a main boss. The miniboss in question? The Darkhammer from the Snowpeak Dungeon! He wields the Ball and Chain (which is the item you get for defeating him) and is fought in a narrow hallway which makes it almost impossible to avoid! He is also only possible to harm from behind, meaning you have to wait for him to attack, clawshot your way across the room so that you are behind him, and then drop and hammer him before he turns around!
 * Conversely, if you've learned five of Link's hidden skills, this battle isn't just easy, it's a one hit KO - the line between That One Boss and Breather Boss is blurrier than you might think!
 * The Legend of Zelda: Spirit Tracks:
 * Skeldritch, the Sand Temple boss, can be a pain, especially due to the sheer longevity of his battle. The first phase consists of catching the boulders he shoots from his spine with the Sand Wand and manoeuvreing them onto catapults before launching them back. Sounds easy enough, but his last few vertebrae are only vulnerable from certain angles, and he continually escalates the speed and intensity of his attacks as the battle progresses. By the time you've reached the last two vertebrae, you'll constantly being floored by his rapid-fire boulder barrage before you can do anything useful, and if you do succeed in catching one, it would be crushed in short order by Skeldritch's next shot...
 * Fraaz from the Blizzard temple for various reasons. His attacks are fairly tricky to avoid, and the ice/fire they leave behind then immediately have to be used against him with the boomerang once he switches elements. For extra fun, later on in the fight the boomerang needs to hit him multiple times before he launches the next attack. You have to do this with a measly four, maybe five hearts.
 * Phytops from the Marine Temple is no joke either. Every time he recovers from a stun, he attacks with two tentacles in a rapid succession that is hard to dodge. In the second half, he also strikes with them during his normal attack pattern in a left-right-both combo that is equally hard to dodge and can easily throw you off the cliff, resulting in another half heart loss.
 * The final form of Malladus can be a royal pain in the ass if you haven't gotten the upgraded Spin Attack. Trying to defend Zelda and having one fireball hit her and then having her start the whole pattern over again can be rather annoying.
 * The Legend of Zelda: Skyward Sword:
 * The first couple of fights against Demon Lord Ghirahim are really frustrating, because he can catch your sword strikes with near-perfect accuracy. He's supposed to be a "Wake-Up Call" Boss that shows you that you can't just swing the sword around randomly and hope to win, but even when concentrating and misdirecting him, it's hard to land any hits at all. The fact that he does all this with one hand, lazily catching your sword between two fingers, just makes it more aggravating, as it's clear he's just toying with you.
 * The second battle against the Imprisoned. The difficulty in this battle is upped considerably from the first fight, as the Imprisoned creates shockwaves with every stomp of its massive feet, making it impossible to come near it and Attack Its Weak Point unless you get really lucky with shield bashes. You're supposed to wait until Groose loads his cannon and stun the Imprisoned with that, but the downside is that this is a Timed Mission; you have to stop the Imprisoned from reaching the temple at the top of the map. In this battle, the boss can grab hold of a ledge and pull itself up, skipping a considerable portion of the map. And the only way to stop it from doing this? That's right, the Groosenator. Which takes him roughly a minute to load after each use. It's not uncommon for a player to stun the Imprisoned with the cannon to land a few hits in, and while Groose is reloading have the boss pull itself higher. And if you save Groose for the times when the Imprisoned pulls itself up? Yeah, good luck approaching the boss with those damn shockwaves everywhere.
 * The third fight against the Imprisoned is more of the same, up until the spike is driven in. From there on out, it's all the player's aiming skill with the Groosenator, and you can't afford to miss. The first time, it's not so bad, as it's a bomb and those can hit anywhere (but if you miss, consider reloading your save file - the Imprisoned is flying). It's the final shot that's the clincher - you have to aim at the narrow traversable ground on the Imprisoned's head, especially near the spike, and that leaves little room for error. If you aim too low, Link falls, and even with the geyser it's not going to be enough time before the rails are crushed and the Imprisoned begins its attack on the Sealed Temple. If you aim too high or too far to the side, you will never make it back in time.
 * When exploring Skyview Temple for the second time, players will encounter three Stalfos in what was previously the boss room. Later in the game this encounter would be child's play, but this is the first time the game throws so many enemies requiring dextrous swordplay at you. Considering this is after the third dungeon, when there are still many Heart Containers to be collected, and that Stalfos can knock off multiple hearts with one swing... it's not a pretty fight.
 * In the last dungeon, you'll have to take on a trio of Stalfos again while a dozen Bokoblins on nearby ledges turn you into a flaming pincushion with their fire arrows. But right before that, you must somehow get past two giant Moblins on a narrow walkway. Both Moblins have unbreakable shields that are as wide as the walkway; hitting the Moblins with your sword is nearly impossible. You could use arrows to kill them, but this only works if you have lots of arrows (you can't leave the room to go get some), and afterward you won't have anything with which to shoot down those archer Bokoblins in the next room...
 * You can run up their shields and hit them in the back. Of course, this gets annoying when the other one rams you off the bridge...
 * Scervo, the ridiculously frustrating miniboss of the Sandship. No Ring Out Boss should ever have that much Knockback. The fight takes place in a narrow, fenced-in "plank", so there's only one direction you can drive him out. And he's fast. He will hit you. A lot. It takes a second or two for Link to recover from the force and run back in, giving Scervo the chance to close the distance. And it's not enough when you finally manage to get him to the edge; you have to do it three times.
 * The actual boss of that dungeon - an Ugly Cute baby Cthulhu which destroys most of the ship - is much easier to kill than that damned robot pirate miniboss if your archery skills are up to snuff. No points for guessing which one you have to fight again later in the game.
 * The rematch mentioned above is a fight against Dreadfuse, a stronger model of Scervo's line of robots who guards the Sky Keep. It's basically the same fight, but with one nasty new trick thrown into the mix: Dreadfuse can electrify his weapons. If you hit an electrified weapon, you get hurt. As if trying to knock him off his side of the arena wasn't already annoying...
 * The final fight with  is exceptionally annoying. First, you have to hit him endless times avoiding his quick attacks, and if you get too far from him he just runs towards you, slashing you with his sword. Once you finally manage to make him fall to the ground, he gets up again, summons a STORM and charges his sword with lightning. Now you'll have to avoid both his skyward strikes and his regular attacks, exposing yourself every time you charge your own skyward strike, which is the only effective way you can stun him (And thanks to some misleading advice from Fi, it can take a long time to figure out that you can even use his lightning against him). Once you have managed to make him fall once again, you'll have to repeat the same process at least once more, and finally deliver the final blow. Oh, and make sure you're quick enough, because he'll get up right at the last moment. Have fun.
 * The Legend of Zelda: Breath of the Wild:
 * The Blight Ganons are, for the most part, incredibly easy and not threatening in the slightest. But Thunderblight Ganon is in a league of its own, and is a brutal Lightning Bruiser who will Flash Step like crazy around the room before rushing in and taking a swipe at you. It's not an easy attack to Perfect Dodge, let alone dodge at all, and you'll want to pull off as many Perfect Dodges as you can so you can Flurry Rush it into oblivion, because the alternative is fighting it normally and having its shield eat through your weapons' durability. Once you deal enough damage, it electrifies its sword and shield, and begins using lightning rods to attract its electricity and fry you if you're close. Unless you came packing the hidden set of Rubber Armor or a ton of electricity-resisting meals, prepare to drop your weapons upon being shocked. A lot.
 * Like all enemies, its health will gradually recover in Master Mode if you don't deal consistent damage. And because it's constantly either zipping out of reach or smacking you to the ground, one of the hardest bosses in the game will constantly heal unless your reflexes are on point.
 * Waterblight Ganon is normally an easy boss: a little tougher than Windblight and Fireblight but definitely not at Thunderblight's level. Then comes its rematch in the Illusory Realm during the Champions' Ballad DLC, which forces you to fight it with Mipha's equipment. And all of a sudden you can understand why : she is woefully unequipped to handle this thing. You have a measly ten arrows to fight it with, which isn't nearly enough when its second phase starts up and has it float out of your reach. And once you run out of those your remaining options suck: your bombs are wimpy and force you to put yourself in the danger zone of its dreaded ice block attack, and your weapons can easily break if you rely on the clunky method of Stasis launching the ice blocks back at it. Urbosa's Fury is a pretty good option, but even it has its downsides. If you use it from far away, you won't have enough time to swim up to Waterblight and smack it around while it's stunned. If you use it up close, its lengthy charge time leaves you vulnerable to one of its ice blocks and you'll have to charge it back up if you get hit. And that's not even going over why the ice blocks are so horrible in the first place: they're huge projectiles that home in on you, and if you get hit you'll be launched into the arena's water, and swimming back to solid ground is such a slow and tedious affair that it can potentially chain ice block attacks and kill you while you're floundering around in the water like an idiot.
 * While straddling the line between Demonic Spiders and this trope, the scary lion-centaur Lynels make for more imposing boss fights than just about any boss in the game. They have a ton of health, are ridiculously quick on their feet, and their attacks will tear through Link's hearts like a hot knife through butter. Don't think you can be cute and snipe them from afar with arrows, because they'll snipe you right back with volleys of powerful elemental arrows that they can arc if you're hiding behind a rock. And since they're technically an enemy, they have stronger differently-colored variants that start popping up later in the game, culminating in the silver Lynels (or even worse, gold Lynels in Master Mode) that have just as much health as Calamity Ganon.
 * And if you tackle Zora's Domain early on like the game subtly nudges you into doing, you get a plot-mandated Lynel encounter way earlier than you're ready for. You don't have to fight it and are encouraged not to do so, but hiding from it is next to impossible, especially since you have to sneak around its lair and pilfer the Shock Arrows laying around to use against Vah Ruta.
 * Much like in the NES game that started it all, Calamity Ganon's no big deal if you fight him the "correct" way. But if you take advantage of the freedom afforded to you by fighting him without getting the Master Sword, freeing the champions, or booking it for Hyrule Castle the instant you leave the Great Plateau with only three hearts, you have quite the ordeal ahead of you. Without freeing the Divine Beasts first, you have to fight your way through all four Blight Ganons (including the aforementioned Thunderblight Ganon) one after another before taking on Calamity Ganon himself, who's got a whopping 8000 HP on top of all the full-health Blights, which will lead to a ton of broken weapons. And the Big G himself has quite the brutal arsenal of attacks, such as Windblight's tornadoes, Fireblight's massive sword, as well as a powerful bodyslam that creates a huge shockwave and comes out of nowhere. He also has the standard Guardian beam attack when you've got him on the ropes, which will do a ridiculous amount of damage and will destroy your shields unless you've mastered the timing for parrying them back at him, or can consistently dodge them (a tall order, given his near-perfect tracking). Oh, and he's not exempt from the gradual health recovery in Master Mode, and given his love of scuttling around on the walls at a surprisingly brisk pace and hiding behind a forcefield or tornadoes, he can recover huge chunks of health before you finally get another hit in on him.
 * Hyrule Warriors: Age of Calamity:
 * Remember how easy Fireblight Ganon was in Breath of the Wild? Well in a twist of fate, it's near-unanimously considered to be the nastiest of Age of Calamity's new-and-improved Blight Ganons. While the slow speed of its attacks was one of its biggest weaknesses in BotW, here it's Fireblight's greatest strength because their awkward timing makes it hard to perfectly dodge and trigger a Flurry Rush, which often results in you getting plastered against the floor by a big, meaty sword strike. Even worse though is its dreaded headbanging attack, where it thrashes its head around and nails you with its long mane of fiery hair. It comes out fast and can be comboed into several more hair strikes when it's low on health, which will burn through multiple hearts if it lands every attack.
 * The Master Kohga and Sooga Dual Boss fight in the "Destroy the Yiga Clan!" mission is likely to be the first encounter that'll really test the player's mettle. It starts off easy since Kohga is... well, Kohga, but once he loses half his health, Sooga jumps into the fray. And Kohga's surprisingly quick belly bump and wide-ranged bomb attacks synergize well with Sooga's powerful wind slashes and his terrifying delayed multi-heart slash attack, leading to a chaotic mess where it's hard to safely attack one's Weakpoint Gauge while the other is aggressively hounding you.
 * If you think that fight's hard, try the Kohga fight at the end of "In the Clutches of the Yiga!". You have to beat him while dealing with a very strict time limit, and Kohga's fighting style is annoyingly good at wasting what little time you've got. And when he loses enough health, he calls in three Blademaster minibosses to further annoy you with their aggressive teleporting and far-reaching wind blade attacks. Oh, and if you didn't defeat him on the way to Kohga? Sooga will join the party, too. Clusterfuck doesn't even begin to describe it.
 * While still formidable opponents, Lynels are generally a lot easier than in Breath of the Wild since you can stun them with elemental attacks and have plenty of ways to force them to show their Weakpoint Gauges. But high-leveled dual blade-wielding Lynels are a lot more dangerous than the rest, because their attacks come out fast, and they're surprisingly acrobatic and can chase an airborne player into the sky. You better hope you've got plenty of charges for your elemental rods left, because you'll need them.

Other Action Games
"A note on mother bear: She's like the rabbit from Monty Python and the Holy Grail...but a bear. She can kill most of your party members with one shot, and like most giant predators, she doesn't need to take much of a break in between killing children. If When Animals Attack were a game, it would be a lot like the mother bear fight."
 * The Core(in the Labyrinth) in Cave Story, which not only fires more bullets than the final boss, and only allows you to fire on it in specifically defined places, but periodically fills the room with water, not only forcing you to immediately rush away from the boss, often during the short windows in which it is vulnerable, but restricting your movement and making it much harder to actually dodge the projectiles.
 * Made worse by the smaller Cores that circle the bigger one. You can shoot them to stun them temporarily, but the only part that takes damage is the main Core, and only when its eyes are open, which only lasts for a few seconds. The problem is that the smaller Cores tend to get in the way of your bullets. If you're using Blade lvl 3, one small Core in the wrong place can really screw you over.
 * Monster X, found a few levels prior to The Core, can also be That One Boss. It shares The Core's invulnerability except at specific times, and floods you with bullets, or in its second stage homing missiles, when it is vulnerable. It also forces the player to ride on it or be run over, and even then you risk being smashed into the walls of the room.
 * is worse than Monster X - her attacks can be dodged, but doing so is often difficult, and Mooks also spawn, which seem not to be much of a threat, until you end up having to kill them while dodging the main attacks. Did I mention that each time you are hit, you will likely lose a level from your weapon? In addition, you have to be very careful with your health as afterwards, you will have to go quite a way for a save point or any decent amount of health refill. At least you have the Blade when you fight Monster X, which wrecks it really quickly at level 2. You can only take TWO OR THREE hits before you DIE! The Machine Gun helps, but only at level 3 or until it runs out of ammo.
 * Custom Robo Arena. For the most part, the battles are moderately challenging, and the rules are clearly defined. The last four 'face' opponents according to the plot are slightly harder, mostly due to being cheaters, but nothing overly major(Snipe is fast but fragile, and his magma stage can hurt him too, Violent Boar is strong but slow, Freya and Katana both have stages that hamper their effectiveness as well). But then, between the first set and the second set of the above, comes . The problem with   is that he doesn't act like a proper robo, instead fighting more like a vehicle: it doesn't flinch when hit, it doesn't go down, and it plays keep-away in order to shoot you dead. And it's VERY good at shooting you dead. Odds are good you'll have to adopt a radically diffrent strategy to fight it. Even worse if you used Soulboost, as.
 * From the Gamecube game, recurring boss Rahu will make you weep whenever you see him appear. He deals enough damage to kill you in three or four hits, whereas his defenses will make you play a game you cannot win. He's so bad that the final battle is a three versus one battle with you, Harry, and Marcia versus Rahu, and even then you're either coming out of it with you being the last one standing, or everyone is going to be down to their last 100 health if that.
 * In the SNES game Illusion of Gaia, the debates rages about which is worse: the first boss, or the married vampires.
 * The spiritial successor to Illusion of Gaia, Terranigma, has Bloody Mary. Unless you're several levels higher than you're supposed to be at that point in the game, your weapons only deal around 1-4 points of damage to her and she needs literally hundreds of attacks to go down. That said, she is quite vulnerable to magic. Which would make things easier if it wasn't for the fact that she is the only boss in the game you can use magic against at all.
 * Baron Praxis is genuinely extremely hard in Jak II (even for Jak II, which was a hard game). What makes things worse is that he's the first boss you fight.
 * Koudelka runs into this a lot, due to its less-than-admirable combat system. One particular example will suffice: Alias, a gunman who ambushes you on a staircase. He runs back and forth between two boxes, shooting at you and usually dealing enough damage to kill whoever he hits. But you can't reach him with a melee attack until you destroy the boxes, and he's somehow immune to magic, meaning he'll continually pick you off as you work on destroying the boxes...
 * Pretty much every boss in La-Mulana has been accused of this, but most are actually reasonable with the right sub-weapon. The only two serious candidates are Sakit and Tiamat.
 * Sakit is the boss of the second field, and a big step up from the laughable Amphisbaena. He stomps back and forth on the screen, dropping rocks on you and stopping to either use a Rocket Punch or shoot magic at you. The only way to damage him is to run up his arm when he uses the rocket punch and attack his face. Hope you went into the Temple of the Sun and found the Knife, otherwise you're just going to be Cherry Tapping with the whip. Did we mention he's immune to all subweapons?
 * Tiamat is the boss of the Dimensional Corridor, the penultimate boss in the game. Unlike Sakit, you can't sequence break around her and come back overequipped; you fight Tiamat at full power, and even then she's a nightmare. She constantly generates bats, and attacks with her tail and her Prehensile Hair. She's also extraordinarily hard to hit with subweapons, so your Pistol shots that you ground for are probably going to go to waste unless you have incredible timing. If you have the Castlevania/Mahjong Wizard ROM combo and the Mace, it's a challenging fight; without those, it's murderous.
 * Bomamba from Ni GHTS: Journey of Dreams is a fight in which you have to tilt a board to get a bunch of cat heads into holes. Sounds easy enough, but the physics are utter rubbish and if the cat head so much as twitches going into the hole it rolls straight over. And, on top of that, you can't pull the board towards you and have to constantly circle the board... by which point the cats have moved to another position and it starts anew.
 * The Chameleon, being that you can spend your first few tries before even finding out how to look for the thing. Not to mention the Cerberus.
 * TeaTea from stage 2 of Myifee's storyline in Ninety-Nine Nights is pretty much the living embodiment of the "bottleneck to make sure you levelled" version. If you try to go at him at level 2, he's essentially impossible to beat, your attacks just barely chipping at his health while he decimates you. If you take the time to kill everything and get up to level 3, your cool new sword and improved stats will make short work of him.
 * Silent Hill 2: The Twin Pyramid Heads, particularly on Hard difficulty.
 * Silent Hill 2 also has, partially due to being the only enemy in the game that uses a gun.
 * The God in Silent Hill 3, while fairly easy on Normal, becomes That One Boss on the Hard and Extreme. She has a ton more HP, requiring you to use your limited ammo and weapons strategically (melee attacking when her head is down during the first half), and once her HP is half depleted, her firewave attacks become much faster and deadlier. Prepare to die many times before figuring this out.
 * For many, Scarlet from Homecoming also qualifies-- not necessarily due to difficulty, but because numerous copies of the game have a bug that makes the fight literally Unwinnable.
 * Most bosses in No More Heroes can be hard before you learn their attack pattern. The Rank 8 boss, Shinobu, may be the best example of this trope, however. She has a large array of hard to avoid attacks, dodges most attacks, and when she gets low on health picks up an instant kill move or two. Similarly, Rank 1 is just obscene. Able to counter every attempt at a grab and dodge most incoming attacks as a matter of course, while doing major difficult to dodge damage.
 * Shinobu's big attack isn't an instant kill, it just does horrifying damage (having picked up every possible health increaser, it may be possible to survive with about four points left). If you want rage-inducing instant kills, Harvey Moisewitsch Volodarskii (Rank 4) and his "Travis-in-a-box" will do nicely. You can escape it by following the game's directions, but you get less time to do it every time you get put in the box, and the game seems to have trouble reading Nunchuk shakes.
 * Holly Summers, the Rank 6 assassin, is just frustrating as all hell, what with her pitfall traps (which have broken Edge Gravity) and tough-to-dodge, uninterruptable Macross Missile Massacre.
 * Rank 2 Bad Girl (on Bitter mode) caused some players to stop playing entirely. Damn gimps...
 * This is, unfortunately, carried over into the sequel. Specifically, the Rank 24 fight against Matt Helms. You're in a small room, there's almost no places to dodge, his attacks are not well telegraphed like any of the other bosses, and he's got a bad habit of just sitting around throwing difficult-to-dodge Molotov cocktails that break dodge patterns and set you up for massive hits. The FINAL BOSS on Bitter is better than this guy on Mild.
 * Well, that last part is an overstatement. The final boss's third form is intentionally weak. As it's mentioned below, the final boss's second form outright cheats on any difficulty. Also, if you want a measure of revenge, play on Sweet, where Matt Helms is in fact, one of the easiest bosses. His attacks are still a little hard to dodge, but his attacks are so slow and infrequent that he barely fights back, he practically stands there letting you beat him as much as you want. You may not feel like a superhero playing through the easiest setting, but it still feels sweet to kick him around.
 * And how about the Rank 8 Fight against in the sequel? The first dual boss of the game, and while only one stays on the ground for most of it, the other will snipe you from the upper part of the stage if you're too far away. Did I mention you're not playing as Travis and your long range attack can't target the upper floor? On the plus side, it becomes surprisingly easy once the first goes down.
 * Rank 50 Nathan Copeland combines this with a Get Back Here Boss; the automatic gunfire plays hell with Travis' autoblock, pinning him in place for indeterminate amounts of time and rapidly depleting his battery. Inevitably, while this is going on (during which time you can neither run nor roll out of the way) you will either take a rocket to the face or find yourself standing by one of the explosive  scattered all over the room. Few things are as frustrating as hearing that little beeping sound, mashing left on the D-pad, and watching Mr. Touchdown stand there like a lump, showing off until he explodes. The Get Back Here Boss comes in after your energy is depleted; making a necessary retreat to the safezone on either side of the battlefield, you recharge your weapon and rush back into the fray...only to be frozen in place again by your autoblock and have your battery drained once more.
 * Rank 51, Skelter Helter, himself is terrible for not only having the ability to keep you off of him for most of the battle from gunfire to no-lag swordplay to even counter moves and fake outs which easily destroy a new player who never played the first, but he's also the freaking TRAINING BOSS and he's harder than most of the following bosses. While he may not be 100% lethal on normal, he will still hassle you more than a lot of bosses halfway through the game, and even on bitter he can be a pain for a seasoned player.
 * Let's not forget the final boss of the sequel. He doesn't look like much, but appearances can be very, very deceiving. It's not too bad until he goes One-Winged Angel and becomes . The beginning of the battle seems easy, his attacks are no different than any other boss but once you knock out half of his health he stops pulling punches and goes all out on Travis. Firstly, he can teleport punch without ANY WARNING and stun Travis before hitting three more times knocking him away and maybe into one of the instant death windows if you're unlucky. Second, once you got his health down enough and you figure that it can't get any harder....guess again as he gains another attack, he will punch forward sending a blast of wind that will immediately knock Travis down regardless and send him flying back, maybe into the instant death windows in the room or maybe into the wall either way he spams this attack too and unlike the teleport punch attack this attack is near-impossible to dodge. Thirdly, the instant-death-Travis-falling-out-and-irritating-many-gamers-to-no-end windows.
 * Rank 7, Ryuji, has a dreadful first phase. You have to drive him off a cliff in your motorbike. A motorbike that can't even make a turn without falling off the cliff. Also, your opponent has a much better control of his bike, and he can push you easily, while you have to get him while he's not charged. The best way to win this is to escape Ryuuji's attack without killing yourself in the process, and wait till Ryuuji kills himself!
 * And then you get to actually fighting Ryuji, who borders on Nintendo Hard even on the easiest setting. He's way faster than Travis, has some of the fastest attacks in the game, has a move that lets him zip halfway across the arena (which he will always spam), meaning you have to work very quickly when your batteries deplete, or just switch to a different sword. He has combo attacks that don't telegraph until you're right in his face, as in too close to dodge. Then, if you've played this game through, you'll know that the second you hear the words "Come out, dragon." you're screwed. His giant energy dragon snakes around the arena, is pretty hard to dodge, and then after a few seconds, Ryuji will use his charge zip while you're running from it. If you end up having to block the dragon attack (which you will) your batteries are pretty much instantly depleted.
 * A commonly mentioned scrappy boss is the Rank 2 fight from the second game, Alice Twilight. She's far from impossible, it's just that she's a very subtle Mirror Boss, her attacks are pretty fast, and the worst part is that one of her attacks is pretty much specifically designed to keep you locked on the ground in Mercy Invincibility, hitting you to lock you down again the second you try to leave it. Another aspect of how hard Alice is is when she's not on her spider-limbs sword-throwing phase, she's on foot, and extremely agile. Agile enough to seem practically impossible to hit on higher difficulties.
 * Okami', as soon as you enter the frigid tundra that is Kamui, you are faced with a mysterious man in a mask... Oki. He's definitely the hardest boss fight in the main game, for one thing that attack where he shoots ice shards at you is tricky to dodge. And when you finally get his health down to zero, he goes One-Winged Angel by turning into a wolf! You've dealt with canine warriors before, but none of them can create copies of themselves, throw bigger ice shards at you, or hit you with a BFS!!
 * A perfect example of That One Boss was Mysterio from the first Playstation Spider Man game. The method to beating Mysterio was straightforward and obvious enough, but the twitchy controls made shooting your webbing difficult at best, particularly while avoiding Mysterio's attacks.
 * Hilariously subverted in the second game based on the movies. His health bar fills up... three times, and then
 * Ultra Mega Mega Man, the final boss of the South Park FPS for the Nintendo 64 (and PlayStation, but that was a forgettable port). Once you get its health down, it starts healing and it's very hard to stop it.
 * Boktai 2. Blue Dvalinn. She don't care how hard you can hit with your 99 Fist Skill and 99 Strength, she'll just stay out of reach and pelt you with darkness, tentacles, and ramming.
 * Durathor, who is fought entirely in brand-new, just got it, Black Django mode, and the most effective weapon for most of the battle is the weak Hammer types. You need to keep flipping from Change Bat to figure out where she is out of the multiple bulbs in one of her attacks, Change Rat to dodge the thorns in another one, and Dark Property just to deal good enough damage. Don't get me started on when that bulb breaks...
 * Curry and Rice, anyone?
 * Real men respect the ungodly killing power of Melon Bread.
 * Most of the bosses in Dark Souls are worthy of being called That One Boss, but the owner of this trope goes to Ornstein and Smough. to give you an idea, you fight these two at the same time, they both have attacks that can easily kill you in one or two hits, extremely relentless and can occasionally give you no chance to heal, and these two are Sequential Boss with the fact that when one of them dies, the other one absorbs their power and become stronger, deadlier, and with the case of Ornstein, bigger. Oh, and did I mention that they get their health completely filled when they do that?
 * Bill & Ben from Seiken Densetsu 3 are often considered to be That One Boss. You fight the two twice relatively early in the game (the first time is right after another boss fight), but they possess all the skills and abilities of Hawkeye's final Ninja Master class. They also move quickly, can lower your entire party's stats at once, and tend to counter any magic or other special attacks with "Shadow Dive", a relatively powerful level 3 tech for that stage of the game.
 * And let's not forget Deathjester, who creates two invincible doubles of himself when you fight him. A fairly annoying, but by no means horribly unfair tactic, until you consider that precisely targeting a melee attack in SD3 is damn near impossible, so unless you've got an offensive spellcaster set up for the fight the best strategy is to keep hitting the "attack" button and pray the game auto-targets the right enemy for you.
 * GameSpot's review of Prince Caspian for the DS had such a reaction with a literal Mama Bear boss: (really had - the version in that link is different, since the site redid it for errors, such as "overlooking some features")


 * Fighting the Emperor himself in Super Return of the Jedi. He spams Force Lightning ALL OVER THE PLACE, which destroys the walkways you're fighting on. It can get to the point where there's barely any flooring left to stand on and it's also possible to fall do your death AFTER killing the emperor!
 * Near the end of Fullmetal Alchemist: The Broken Angel, there was one of the most painful boss battles in the game. It consists of a revisit to the three chimera bosses you fought individually earlier in the game: the Behemoth, the Griffin, and the Serpent. Now by themselves, these guys weren't so bad, but fighting all three at once was beyond ridiculous. The Behemoth takes very little damage at a time and has the capability to heal itself, and also fires homing projectiles. The Griffin spends most of its time out of your reach, flying around above the arena and dropping a constant stream of fireballs. Meanwhile the Serpent enjoys playing a game of Lethal Whack-A-Mole with you as it randomly pops up from the pools of water situated around the arena and using a flurry of attacks to ensure that coming near it will take a large chunk off your health. It goes without saying that this fight is a living hell for the player.
 * Then there's Pride in Dual Sympathy. He's not too much trouble most of the time, but when you play as Roy...
 * In Curse of the Crimson Elixir, the second time you fight The Phantom/ . She never stays still and will more than happily dance around Ed's attacks then kick combo him in the head. She also takes little damage from attacks (even max level alchemy bombs} and at around half-health begins to summon several giant golems that fire projectiles all over the battlefield. Making it very easy for poor Ed to be juggled to death via Beam Spam.
 * Yaha and his gnomes from Drakengard 2. When there aren't a whole lot of noisy gnomes attacking Nowe en masse, the floor randomly lights up with circles that produce highly damaging stalagmites. And once that's over, there's the giant gnome/rock monster thing itself... with a tendency for overly powerful attacks, including one that is nearly impossible to dodge. Rinse and repeat until you kill it. Ugh.
 * Gismor also qualifies. Instead of staying within weapon-range like a nice evil entity, he either jumps around the four platforms that you cannot reach because they are about three feet away from the edges of the cross-shaped walkway that you can stay on, even though your party members can jump about twice their height, or stands at one of the four arms of the walkway and shoots lasers at you that you have to move in a specific pattern to avoid being killed by. While on the platforms, he fires magical energy balls at you that, if you manage to break them, give you a magical boost, but are about as easy to hit as Fire Keese. And you need magic, because you have to hit him with magic to get him to move to the walkway.
 * Good luck beating the boss of Area 6 in Blaster Master without cheating. It's a palette-swap of Area 2's boss, but it has more Hit Points, projectile attacks in addition to its claws, and gives you very little room to maneuver.
 * The boss of Area 5 is a pain in the ass to beat, too. To make the long story short, those bubbles he shoots will block your shots, and he spews out more and more as you wear him down. It doesn't help that the doesn't work against him.
 * The third Owata clone in the The Life Ending Adventure fit this trope to a T. The first one is easy, the second one is pretty hard but the third one is almost unbeatable. The fact that he heals when he's low on HP and that you are the One-Hit-Point Wonder don't help at all. Of course, the whole game is obscenely hard, no wonder I Wanna Be the Guy was based on this.
 * in Star FOX Adventures.
 * One thing that makes this fight way worse than it should be is Normally this wouldn't be an issue. And it isn't... later in the fight. If he gets you with it while he's still in the first form,
 * The Hulking Lungfish from Psychonauts. Feed It a Bomb. Fine; not a problem. However, the fact that it's a Cowardly Boss who forces you to go through a long, difficult Advancing Wall of Doom segment between attempts to damage it makes the fight against it tedious, difficult, and annoying. Luckily, beating it is well worth it, for the awesome, Godzilla-movie parody level you get to play aferwards.
 * Dynamite Headdy has a few tough bosses near the end, but Izayoi/Nasty Gatekeeper is That One Boss for two reasons:
 * The traditional reason; she's hard. She has a lot of deadly moves and she uses them very fast. Every time you hit her, she strikes at you five times at hyper speed. It's nearly impossible to avoid if you don't know what you're doing, and still pretty tough if you do. Headcase (your source of powerups), when he is there, is spinning around wildly in the nasty gatekeepers grip. Most bosses, while perhaps on the hard side, can hardly begin to prepare you for this fight. So even if it's not the hardest (and it may be), it definitely sticks out.
 * It could be debatable for hunting down and killing Pulaski in Grand Theft Auto: San Andreas. When you start the mission, the car you came in (assuming you came to the starting point by car) will usually have vanished. Pulaski drives a Buffalo, a very fast and durable sports car, while you're stuck with a weird looking off road car that handles like crap. To even get Pulaski to get out of his car, you have to wreck it by either making it flip over via ramming or pumping it full of lead with a drive-by. Even when Pulaski finally bails, he shoots you with a friggin' Desert Eagle, the most powerful handgun in the game which can knock you down. If he knocks you down with it, he'll keep shooting at you until you're dead. Oh, and his health is sky high, requiring a lot of firepower to take him down. Although it is possible to run him over or use explosives, usually your car is near a total wreck by then and Pulaski's gun can bring it to a near total explosion, forcing you to bail.
 * "Durable" is an understatement. Firing a minigun at the car in the time before he gets in it doesn't destroy it. You can, however, exploit the physics engine by using the impact from the minigun to flip over and automatically destroy the car.
 * Sly Cooper has two bosses that fit the bill. First is Mz. Ruby. She's basically just a musical rythym minigame, however, you can only screw up a maximum of three times in about three minutes before having to start the whole fight.
 * The honor of being the hardest boss belongs to Clockwerk, the games final boss. His first form is simple enough; just circle to avoid the energy blasts, and shoot whichever part Carmelita electrifies. After he crashes into the lava, he rises like a phoenix and things get difficult. You have to shoot the electrified body parts as before, but this time he launches electric rings that zap you unless you place yourself perfectly in the middle. Maneuvering through the rings is frustrating enough, but even after you empty his lifebar for the second time, there's still a third stage, and it's the worst of the lot. Now you have to run across some rocks and debris over a field of lava, dodging vertical lighting blasts and rotating security lasers on your way to Clockwerk's crashed form. And the worst part? 1-3 hits (depending on how many horseshoes you picked up) and you have to start the fight over from the first phase.
 * Starscream in the Transformers Armada video game. Even on the ground he's insanely fast when he's not walking straight at you. When he takes to the air and starts strafing it's hard enough to figure out what direction he's coming from, let alone actually landing a hit on him. With the right combination of Mini-Cons you can get the weaponry necessary to beat him without snapping your controller...which would be great if he wasn't the second boss of the game.
 * See also Cyclonus. The battle begins atop an ancient pyramid, and one of Cyclonus' first acts is an unblockable (and probably unavoidable) throw that usually sends you sailing off the pyramid For Massive Damage. He follows this up with a strafing attack that eats up your life, and seems to be unavoidable for everybody except Hot Shot, who can avoid the attack by transforming and hiding underwater.
 * In Prince of Persia: The Two Thrones, this overlaps with the Dual Boss. You fight two baddies, one who carries a sword and parries all attacks, and one who carries an axe and is too heavily armored to hurt. In order to damage them, you have to first attack Sword Guy ineffectively until Axe Guy leaps at you from behind. Dodge so the axe gets stuck in the ground, giving you a very short window to run around behind Axe Guy and hit him, once. Repeat this for many hits and eventually it will trigger an Action Commands scene that will let you do a small amount of actual damage to the bosses. Then do the whole repetitive thing over again, twice, to kill them. If you fail to dodge the axe, you take 50% damage and get knocked down. If you miss the timing on the runaround, Sword Guy will unblockably combo you to death. God help you if you screw up the Action Command. Oh, and did I mention the surrounding Ring of Fire that hurts you and not the enemies? And that this whole thing happens immediately after the chariot-racing Scrappy Level, without a save point in between? And the level isn't even over once you beat them. Yay.
 * Any boss battle with in Prince of Persia: Warrior Within could be considered That One Boss, simply because if you didn't the follow the strict pattern of the fight the game gave you to the tee, the bitch would take half your life bar away in a flash.
 * Prince Of Persia 2008's downloadable epilogue has the final battle against in the Ballroom. Players may better remember it as ELIKA! THE THRONE, THE THRONE!
 * Ultimate Spiderman has quite a lot of these. The second fight against Venom and when you fight Electro are awfully hard. Green Goblin, who looks like the Hulk on fire, is hard considering you have to dodge fire balls and while doing that you'll sometime miss your chance to harm him. You then have to go into a flaming church to fight him and it's hard.
 * The hardest of all is Carnage. You play as Venom but he fights similar to you. When you beat him up enough he hides behind a gate that is very hard to move and then he goes into another one. He also fights hard and can heal again afterwards. This guy had to get his expert gamer friend to beat him up for him and he cussed during it.
 * Speaking of Spider-Man, in the N64 Spider-Man game, Venom is ridiculously hard considering that he's only the second boss in the game. Walk too far away from him, and he pulls you in with an unblockable attack; Get too close to him, he grabs you with an unblockable attack. He has twice as much health as the player, and one of the only too meager health pick-ups is under a larger container which takes a few seconds to lift--meaning that if you try to grab it, he'll probably be able to attack you.
 * Another Ultimate Spider-Man example comes from the iPhone game Ultimate Spider-Man: Total Mayhem. Most of the game is a cakewalk, but only because it's practically refreshment following The Rhino, the very second boss. Most of the later bosses have the benefit of letting out health power ups every few punches, but with Rhino, there is no such mercy. You can expect a third of gameplay time going down the drain as you face three stages of relentless smackdown from the brute and his ridiculously powerful charges.
 * Spider-Man: Web Of Shadows, the console version, brings us Electro. The fight comes not long after another tough boss, Venom, and the player is probably hoping for some nice breather missions afterwards, but instead, your friendly neighborhood electrocharged criminal crashes the party and starts spazzing out on everyone. Too much of the fight relies on you web-slinging and chasing Electro through the city; while web-slinging is fun when you don't have to be too precise with it, this fight reveals just how imperfect the mechanic is, especially because you lose and have to start over from the nearest checkpoint if he gets too far away. And you can't easily track him with your eyes or spider-sense, because he simply teleports from place to place. When you finally do get to fight him, prepare for a tough, confusing light-show that can easily camoflage attacks. Perhaps the worst part is that after all this, Spidey isn't even the one who gets to land the final blow.
 * Kakistos in Buffy The Vampire Slayer: Chaos Bleeds. You fight him in an cramped area where he is using three magical orbs to restore his health: you have to hit each orb three times (and by that I mean you have to go and hit each orb once, then hit each orb again, and then once more) to destroy them. While zombies come out of the ground and get in your way and attack you. And Kakistos hits you with fireballs and flaming oil bombs that chew right through your life bar, if he doesn't just kick you upside the head. And then when the orbs are destroyed, you still have to take him out. With zombies still coming. Strange how an old vampire is harder then the source of all evil.
 * Ys: The Oath in Felghana is for the most part a cut-and-dry PC reimagining of the third game in the series, Wanderers from Ys. However, one boss went from laughably easy to downright nightmarish in the transition from sidescrolling Action-RPG to top-down Zeldalike.
 * Death Faleon is UNQUESTIONABLY the hardest boss in the game, bar none, and it's especially ridiculous considering what a complete pushover he was in the original Ys 3. Seriously, even when properly leveled (which you won't be), this guy is an complete nightmare. He's got more attacks than any other boss (and those same attacks track you with incredible accuracy), a shifting elemental weakness, he moves extremely fast, and he takes an absolute load of punishment. Surprisingly, despite the MASSIVE difficulty and complexity spike compared to previous bosses in the game, he gets the same boss theme as everyone else. And remember: he's got no storyline significance. Death Faleon is just a midboss.
 * Almost every boss may have shades of this trope due to being so much harder than what's around it. The one that really sticks out is Ligaty: Firstly, there are three of them; one has a weakness to physical attacks, one to Wind magic, and the other to Fire magic, and they each use their respective weakness against you (strangely). The troubles start when you realise your choices are to either attack the physical one, who has a habit of breaking out of hitstun and attacking anyway, or your combo could send you right into an attack from one of the others. Going for the wind one, in which case wind magic limits your movement a few seconds and removes Mercy Invincibility, potentially allowing you to take multiple hits in a row. Finally you can go after the fire one, who you can at least use ranged attacks on, but the aiming can be tricky and while you're focusing on that it's very easy to walk into an attack. Add all that together and it verges on a Sadistic Choice. To make matters worse the less there are the tougher they get, so the final one is nastier than all three combined. Pretty much the only choice is to exploit one attack they use when all three are alive that makes them stay in place a while defenseless, then continue until you've weakened all of them enough that you can quickly destroy all three before the stragglers get going.
 * There's also Zirduros. The only weakpoint is its back, it's quite agile while constantly peppering you with projectiles AND the weakpoint is capable of launching mines (which hurt you if you're attacking it in melee). After losing some of its health it can launch a laser that covers a large area in front of it and only gives you a split second to evade. And any of this onslaught is capable of killing you in around 10-12 hits unless you're really over leveled. While not the most damaging method, pretty much the only safe way to harm it is to to charge up Earth attacks and exploit the invincibility frames it has. Even better, if you do the dungeon in a certain order this can be the next boss you face after Death Faleon...
 * In the original Ys 3, the crystal boss in the Cursed Mine was the hardest, if you don't do some serious Level Grinding beforehand. And the Time Ring is pretty much required here.
 * The red ape demon in the Famicom port of the original Ys. Jumps around the room firing highly-damaging nearly-undodgeable omnidirectional projectiles. It's nearly impossible unless you break sequence and go further up the tower for the Infinity Plus One equipment
 * Gundam Battle Universe doesn't have annoying bosses but some of the Extra missions will make you cringe. The two most famous ones being having to face 3 Psycho Gundams who surround you and will kill you instantly if not dodged and the other is to carry 5 boxes of goods amongst respawning weak mooks as well as the Lanfressia who will ignore flinching damage and always activates its SP attack. If you want the S rank and operator limit unlocked, you have do this.
 * Eternal Darkness' has the essence guardian. Immune to gunfire, too far away to stab, and shoots various projectiles at you. You have to dig in and shoot magickal attacks at him, in a certain timed inteval. At three points he creates and shrinks a barrier till you're within stomping distance, and stomping is an insta kill.


 * Peg Leg Pete in Mickey Mousecapade. He throws a constant stream of daggers that randomly change direction and are nearly impossible to dodge, and the only consistent way to defeat him is to resort to cheap tricks like inching up the ladder and shooting, or putting the invincible Minnie up there if she has her stars. He reappears as a Degraded Boss in the Castle, but is even worse there, as there is no where to hide from his daggers. Pretty much the only way to get past him without losing a ton of health (afterwards, you have to face the Walrus, a Boss in Mook Clothing, followed by Maleficent, the Big Bad herself, also That One Boss) is to hope that you find an invincibility fairy behind one of the windows. And god help you if you left the key to the Boss Room behind, as he will respawn and One-Hit Kill you if you backtrack.
 * Mass Effect. Therum. That One Krogan. That. One. Goddamned. Krogan.
 * An optional Mass Effect 2 That One Boss features in the Kasumi's Stolen Memory DLC in the form of Donovan Hock at the end of her loyalty mission. At first it seems like a standard gunship battle, of which there are two in the main game. This one is different however, in that squadrons of Eclipse mercenaries and LOKI mechs will continually spawn that you have to take care of while Hock pelts you with fire from his gunship. Oh, and when you deplete the ship's shields, they simply regenerate to full. Also, the way the cover on the platform where you fight Hock means that there's a good chance he'll be able to fire at you from behind or the side while you're taking cover from the Eclipse mercs swarming the platform. Adding to this, your party for the Hock fight consists only of Shepard and Kasumi, since you can't take a third partymember to Bekenstein. It becomes pathetically easy after Kasumi uses some fancy acrobatics to permanently disable the gunship's shields, but to get to that point you have to survive several large waves of Eclipse mercs.
 * Far worse is the  fight in the Shadow Broker DLC, who puts all the other bosses to shame. Obscenely difficult on insanity mode. Teleports around randomly, can take the entirety of the most powerful sniper's ammo in headshots before depleting her barrier (the first of 3 lines of defense)and similarly strong armor/health, summons additional mooks, has attacks that literally two shot kill you even with all health and shield upgrades, and is generally a huge pain in the ass. Pretty much the only thing about this fight that's not ridiculous is there's a huge amount of extra ammo lying around so you don't have to worry about running out of clips like some bosses.
 * In Aquaria, Octomun definitely qualifies. The only way to defeat him is to get in close and fire at his weak point,  which brings you in range to be hit by a devastating tentacle attack. To cap that, he spawns enemies that can blind you, can darken the entire playfield by emitting ink, and fires a near-constant barrage of homing shots. There aren't any tricks or shortcuts, either. Ouch.
 * King Jelly is a horrible mook spawning monstrosity complete with nigh unavoidable lasers and is completely invulnerable except for a very hard to hit rotating Weak Spot. The only upside is that defeating it gets you the undeniably best armor in the game.
 * Keith Courage In Alpha Zones: Mr. Roboto(did they get sued for using this name?), the boss of the Toxic Zone. A floating Humongous Mecha who moves in an arc pattern and takes off a full heart with each hit, unlike the other bosses, and has much more HP than previous bosses. Even worse, the Final Boss is a suped-up Palette Swap of him with an invincible purple mecha companion(a Dual Boss).
 * Biomeka from Wonderboy In Monster World, plays this to a T. 2 Forms with a Yellow Green Bar (Highest HP in game), uses Laser cannons which have a full Blue Bar (Highest HP for regular monsters) and those cannons can respawn, and on the second form, has a conveyor belt with a Buzzsaw on it in addition to the laser cannons. You have better have got enough Power or Thunder magic, because you will need it.
 * Bunji Kugashira from Gungrave can go straight to Hell. The fight starts with him sliding at you; if he hits, he launches an attack that takes out your shield and a quarter of your health. If you dodge, he can turn mid-slide to catch you. If you get too close, he has a melee attack that blows your shield. What truly makes him a bastard, however, is that he can heal if he gets behind cover. The level has two pillars which he gleefully hops around, healing himself every single time you're out of range. The only, only way to win is to throw yourself on him and fire until he's dead, channeling Demolition Shots into healing and never letting him get out of the center of the arena (if he gets to a pillar, the fight will stalemate thanks to his regeneration). Topping it all off is that he has his own "Graveyard Special" (the boss fatality shot that Grave's been using up to this point, which Bunji can use at any time), as mentioned before. He'll punt poor Grave, sending him flying and come crashing down, causing massive trauma.
 * And then
 * Overdose gives us a Sequential Boss, a series of Robot Tanks. At first you're only fighting one, but it is impossible to hit with your melee weapon (which is REALLY bad if you are playing Juji Kabane's campaign, because Juji is the Speedy Melee Character of the three protagonists) as you are immediately knocked back and causes moderate damage. It's also fast and will constantly spam a barrage of missiles or machine gun fire, and can climb on the walls and slide around, pelting you at all sides. And just when you think it's over, when the first tank is destroyed, two more tanks show up...
 * The Millenion Leaders Hybrid boss in the laboratory stage. You fight it in a circular arena, but every time you empty its life bar, it just regenerates. It also has a painful sword swipe and explosive projectile attacks that can totally destroy your shield and cause high damage on higher difficulties, on lower difficulties they won't usually break your shield but still often leaves you with a sliver of shield left, and there's no safe cover in which to regenerate, as you'll want to save your precious Demolition Shots for the generators. You're supposed to wail on the boss until your Mission Control tells you to target the generators and destroy them to stop the boss' regeneration. And all the while you're trying to attack the generators, the boss is throwing said explosive projectiles and sword slashes at you. And when you manage to defeat it, when you're riding the lift to escape, the boss comes back and can now body slam your character, which usually breaks your entire shield. And you have 150 seconds of game time to kill it, otherwise your character won't escape the Collapsing Lair in time.
 * Ballabird Lee in the original game can be highly irritating, bouncing around the fight area in unpredictable patterns, chipping away at Grave's shield with his machine gun hand and a "grab/throw" move that's hard to see coming because of a slightly screwy camera. Lee's normal sword attack also tends to hit like a Mack truck, often breaking a full shield on Hard or Kick-ass.
 * Sherry MacDowell Walken in Overdose. She's extremely nimble and fast (even faster than Kabane). Being so fast, it's nigh-impossible to pull off a successful Charged Attack against her. You also fight her in a highly confined area and there is nothing to hide behind to regenerate your shield. One of her major attacks, for lack of a better description, closely resembles a Dynamic Entry. She will use it, and use it often, and has the possibility of knocking off almost 2/3 of your shield power. And it knocks you down, and eight times out of ten by the time your character gets out of their recovery animation, Sherry will KICK YOU AGAIN.
 * Fangoram in Overdose is also insane. Not only does his gun do insane damage but he'll randomly fire it in every direction and then smash the ground, causing metal support beams to explode out of the ground and fill the level...which makes everything REALLY slow and then you can't see him until his gun shots go through the beams and hit you.
 * Modarchive Story is a shining example of Nintendo Hard in general, but Doragon is utterly ridiculous. When and where it will spit fire is RANDOM, and you die in one hit. I'm not sure how many times you have to hit him, but it surely is way too many. Oddly enough, it's the boss of one of the easier stages, and the Scrappy Level (Zepsi Industries) has perhaps the easiest boss fight in the game.
 * The robot guard Biscarsh in Klonoa 2 is a nightmare. The first form is pretty easy, providing you know what you're doing. And then it Turns Red. First of all, it tries to turn Klonoa into a Dream Traveller pancake requiring you to grab an enemy, run into the middle and jump over his head in order to hit his weakness. Then he has the nerve to send homing missles after you whilst floating in the air!
 * Kazdan. Effing. Paratus. The little bastard skitters around the stage way faster than you can, and often slips out of your lock-on. Force Push and Grip are next to useless, as he blocks them nearly every time. He, on the other hand, can break your block with every attack. The only way to really damage him is Lightning...which you only receive at the beginning of the level, and thus do not have time to power up. Damage him enough, and he leaves the stage, hurling detritus at you. If you don't dodge, you take damage from the hit and the fall. Damage him some more and he summons Junk Titans (essentially giant, tough minibosses) to fight you...twice. The highest difficulty is... difficult.
 * Comparable is Shaak Ti, who, unlike other Jedi bosses, cannot be Aerial Ambushed, a peculiarity she shares with Kazdan Paratus, which is normally your choice to hit a boss For Massive Damage. Then there are her deadly saber combos, her charge attacks, which leave her invulnerable while charging, the fact that she constantly summons Felucians to annoy you, and the exploding slime... thingies on the sides of the arena, which explode if you get too close, which can lead to annoying situations where you're juggled between said exploding slimes after getting knocked into them by Shaak Ti. Luckily, you can do the same to her. And in the second half, she may occasionally go offscreen to have the Sarlacc's tentacles wail on you, which is especially annoying if you have to keep Felucians off your back at the same time. On Sith Master, this battle is... hard. This is, however, somewhat alleviated by the awesome music and the fight itself pretty much being a Crowning Moment of Awesome.
 * In the Wii version, Chop'aa while riding his basilisk. The bloody thing is too large for Pushing or Gripping to work, it's bloody fast, it has extreme amounts of health, and stopping to unleash some Force Lightning all but guarantees getting your head swatted by a giant claw, even if you try to jump away. At least Chop'aa himself is a cakewalk.
 * Also from the Wii version, Kento Marek, specifically during the rematch in the Jedi Temple. It's as if the man somehow perceives reality at a faster rate than you can; he blocks or counters most frontal assaults or Force attacks, seems to run and jump faster, and will catch you if you're not constantly moving.
 * In the 360/PS3 version, aside from the poorly-implemented boss fight against the Star Destroyer, there's also the final boss of either path.
 * The sequel has the Gorog, whose fight never seems to end, and the final boss is
 * Valis Phantasm Soldier (the first game of the series) has two of these. The first one is the twin-headed skeleton dragon (whose most damaging attack - the lightning spell - CAN be blocked with a well-timed spell casting). The second one, which is INFINITELY MORE difficult, is, who has the Final Flash spell that deals just under 50% damage every time it hits you, and cannot be blocked or countered. Oh, and guess how strong it is in your hands?
 * Jet Force Gemini features the Eshcebone Mantises. Yes, there's two of them. Giant cyborg mantises with a ridiculously wide variety of attacks, fairly small weak points for most of the fight, a dark battlefield, AND THERE ARE TWO OF THEM OH FSM WHYYYYYYYYYYYY
 * The Ecco the Dolphin games are just plain hard in general, but the final boss of the first game stands out less because of her own difficulty and more because if you lose, you have to repeat the five minute long scrolling level with no checkpoints where a wrong turn means instant death. And, as if to further taunt you, the game gives the password to her chamber after the credits roll.
 * This was fixed in the PC port, where losing against her just starts the fight again. Also, IIRC, the scrolling level was given checkpoints.
 * Asterite, anyone? You have to precisely hit 4 targets out of 32 that constantly move around, if you hit anything else you have to start the sequence over. All the while it shoots lightning bolts at you and you are running out of air. It also takes at least a minute to get to it from the start of the level and there is no checkpoint when you do, so if you die you have to start over from the top of the level.
 * In Defender of the Future, the generator in "Sleeping Forces of Doom" is not actually that hard, but best of luck figuring out how you're supposed to destroy it in a timely manner, without frantically using moves at random hoping something happens or grovelling over to GameFAQs for help.
 * Defender's final battle is a Womb Level with very little room to manuever, a slightly less-than-intuitive way you're supposed to go about destroying, and not one but two time limits counting down to your inevitable doom: Ecco's air meter (which is nigh impossible to replenish in this level), and the steadily rising pool of from below that will eventually flood the chamber and kill you.
 * from Fatal Frame 3. She absolutely LOVES this move where she turns the screen black and white, makes it so dark that you can only see yourself, you run like you're moving through jelly, and she chases you. If she touches you, it's a one-shot kill. It's hard to even SEE her, let alone avoid her because you move so goddamn slowly.
 * As difficult as that boss can be, the Kusabi in chapter 8 was harder. He's a challenging enemy in his own right, and you have to fight him with Kei, by far the weakest character. Of course, if we're talking the entire Fatal Frame series, the Family Master from the original game is That One Boss.
 * All the bosses from Fatal Frame 1 qualify. Considering the game mechanics made it possible for the ghosts to move faster than Miku, it was very difficult to get a lock on the ghosts that liked to either strafe or teleport. The Family Master was tough, but Ryozo Munakata was just as bad since he mainly moved by teleporting around the area. Then, if you're playing on Nightmare Mode, he has this nifty attack where he mesmerizes Miku into coming towards him so that he could grab her. Then there's the end boss  whose ONLY attack is the insta-kill one and who could only be hurt by a fully charged shot. Oh and she regenerates health over time.
 * While he's not technically a boss, the Monk from Fatal Frame 1 is another spirit who was a pain to fight. He not only likes to teleport, but he also tends to bumrush you so that he can deliver a nasty kick to the head. He usually has a fairly large amount of XP and getting a charged shot is annoying as hell. While I love that game to pieces, the enemy AI was ridiculous sometimes.
 * Weldar from Banjo Tooie. At the start he shoots energy balls (simple to dodge), but then he tries to suck you in. You shoot a grenade in him (if you're lucky), then he shoots some baddies at you. Beat them and then he follows you around. After that he electrifies the floor in tandem with the same moves. To add insult to injury, his Boss Room is very out of the way, and you don't (directly) get a Jiggy for defeating him.
 * Lord Woo Fak Fak in Banjo-Tooie. He moves so quick, and unlike Mr. Patch he moves into you -- not hurting you but making it impossible to aim and. Hitting him becomes a matter of luck. Even worse, you fight him underwater, in a ridiculously confined boss room, making it even more impossible to put enough distance between you and him to manuever effectively.
 * Mr Patch, in all of his incarnations. In Banjo-Tooie, his erratic movement and Kazooie's wonky flying made wasting Grenade Eggs almost inevitable, and the slow flying made dodging the exploding beachballs a nightmare. Oh, and he gets smaller every time you hit him. Nuts and Bolts had you face him two times - in Nutty Acres, his patches are less obvious and your plane (if you have one) won't be advanced enough to turn quickly, meaning you either have to wrestle yourself into position or slam into him too many times, and in Banjoland, dragging him into the cactus is difficult because he breaks away every time he gets a puncture and the helicopter controls (assumng you used a helicopter) are wonky-tastic.
 * Any battle against Axel Gear involving two Mechas in the Rocket Knight Adventures series. On Normal, they're bearable. On Hard, you better hope you have full health walking into it. And, what's worse, the SNES Sparkster game has a special surprise for those that defeat the Final Boss on Hard which makes the Axel Gear fight look easy.
 * The God of War series has a handful of these, but the final fight in the original game against the eponymous God of War is a bitch on any difficulty other than medium, plus it's a two-parter with an extremely difficult War of the Clones wedged in between. Pure evil.
 * God of war II. First Titan-mode minotaur? Not much of a problem. Number 2? A resilient boss with few openings AND infinite respawning harpies that can 3 shot KO you on titan. There's a reason most guides for this fight use the phrase, "metric assload of luck" liberally.
 * Theseus on Titan, who serves as a huge difficulty spike, even compared to the Nintendo Hard opening act. He can pretty much combo Kratos to Hades and back in his first form, proving to be more of an unpredictable opponent than the Mooks you've been facing so far. And then comes his second form, where he starts spamming projectiles at you from safety, starts summoning two Minotaurs at once to fight you at the same time, and causing large crystal spikes to pop up from the floor which, on Titan, pretty much one-shot you. Add all of this on top of the fact that the only way to hurt him in his second form is to shoot him with your incredibly weak bow. And your magic is limited, so the only way to restock it is to run around dodging attacks and killing the Minotaur for blue magic orbs. And it'll take several cycles of this before you even get the chance to finish him off. If you die, you go back to the first form. Have fun.
 * The Cerberus Breeder in God Of War 3. He spits out kamikaze dogs at you that explode. Sure you can kick them back at him but they don't do a lot of damage.
 * Descent: Many of the bosses, due to being armed with the most powerful weapons in the game on top of being accompanied by a small army of Mooks, and some of whom are Mook Makers to boot. However, the Ice Boss from Descent II takes the cake for pure frustration. He fires homing Flash missles (which blind you) and an Omega Cannon (the strongest primary weapon in the game) which has been haxxored so that it also blinds you. Meaning that unless you stay up in the passageway leading into the Boss Room (which protects you from most of his attacks), you'll likely be flying completely blind for the entire battle. And he's immune to energy weapons, meaning that the only two primary weapons that even affect him are the Vulcan and Gauss cannons, for which ammo is rather limited.
 * The Fire Boss may be even more frustrating. Instant-kill homing Mega Missiles + super Phoenix Cannon + random teleporting + lack of cover = pain. If you wasted the cloaking device, you're fucked.
 * Luigis Mansion has Boolossus, a horrendously hard boss battle that involves freezing a bunch of tiny boos in order to defeat it. Unfortunately, as the number of boos get smaller, they become harder to hit, until it's almost nigh impossible to hit the very last boo with your freeze weapon. And they know when you are using the ice, because they run away when you do. Its almost impossible to get them unless you shoot while they dive bomb you, and when that happens its like impossible to aim before shooting.
 * Technically a mini-boss, but Sir Weston is easily the most difficult portrait ghost for the perfect run. His room is covered in ice, so it's very difficult to suck up him up in one go.
 * The final boss in True Crimes: Streets of LA. Not only does it not make any sense, but this is where the difficulty spikes horrendously. Specifically, every single boss in the game up til the end could easily be beaten with simple Button Mashing, whereas the final boss had to be beaten with an actual strategy (blocking then counter-attacking), which most players would never have guessed since the game never hints at this and Button Mashing got them all the way to the end just fine.
 * Onslaught (2009 FPS) has the Mission 8 boss which has turned into That One Boss for many players. It might be because the boss has a tendency to correct its aim while using its extremely damaging beam attack that you're supposed to sidestep. Also the small arena and spawning smaller enemies make it very easy to sidestep into an obstacle, making even the usually easily dodged jump attack a threat.
 * Mischief Makers has the second fight with Merco, when he brings his Phoenix Gamma. Getting the Gold Gem for that boss is beastly hard, and it's respectably hard just to beat it at all.
 * Shadow of the Colossus is a very enjoyable, artistic action-adventure game. The 9th colossus is a complete bitch. Essentially, he's a giant turtle. The only way to successfully climb onto him (the point of the game) is to lure him onto stepping on some geysers. He frequently steps over them or walks just a few feet near him, making that an exercise in frustration. If you get him to step on a geyser, you have a small window of time to shoot the underside of his feet so he flips over. Then, you have to run around and climb on his belly. When you're about to finish climbing, he stands up. If you aren't positioned right, you fall off. If you manage to stay on killing him is easy. The boss isn't incredibly lethal and doesn't sound hard to beat in text, but all the components make him incredibly aggravating and unfun to fight him in the game.
 * With the 9th, at least you have a reasonable chance once you get on, it just takes time and luck. The 16th and final colossus, however, is (metaphorically, not literally) a tremendous cock. All the wonderful landscapes in the game are NOT present, and the whole fight is in shades of black and very dark grey. Just in case you have the superhuman vision to dicern color in this mess, the camera abrubtly turns into a big pile of ass, too. Oh, and if you fail any part of the second half, you fall off and have to do it all over again.
 * The eleventh Colossus? A comparatively tiny (only the size of a VW bus or so) colosus, something like a cross between a pit bull and an actual bull. If you happen to fall into its pit and fail at dodging its attack even once, it'll knock you around with abandon, stunning you completely with each blow and attacking again just as you begin to wake up.
 * The 4th Colossus can eat a bag of ass. For those who don't know, it's a giant horse. The area around you if completely surrounded by...tombs probably. This thing's only climbable area is on its tail, which is too high for you to reach. So you get it's attention near one of the tombs until it starts attacking the tomb like an ass. You need to run to the other side, since all the tombs ar connected under ground. The issue? 1. You need to be witin striking distance for him to even GIVE a crap you're there. 2. You need to be FAST, and since a gentle nudge will send Wander head over ass, that's difficult. 3. The Colossus has ADD, and making him stay near the tomb in time to run over to the other side, let alone to the colossus is pretty damn difficult.
 * The 15th colossus, Argus, requires the player to complete a very convoluted set of maneuvers in order to even have a chance at reaching his weak spots. Dormin's hints are cryptic as usual, and it can often take players a long time to figure out the correct solution to the puzzle. This is not aided by the fact that Argus walks faster than Wander can run and is constantly trying to smash him to bits while the player attempts to think.
 * The third Colossus, on normal mode, is a surprising jump in difficulty from the first two, with the added inconvenience of there being a long drop below the arena, necessitating a long climb (and possibly a lengthy swim) to get back to the boss if you fall off. On hard mode, the thing's capable of killing you in a single hit from the attack you have to get it to use before you can climb onto it (at least twice if you're using the normal strategy, one of which must land on a specific position), and it has an additional, necessary weak point located inconveniently out of the way of any ledges.
 * Zombies Ate My Neighbors has the battle against Dr. Tongue's spider form. First off, you have to battle it, unlike the rest of the MiniBosses who may or may not have to be killed to complete the level. Unlike those other bosses, you are given no warning of its appearance; when the doctor character had been encountered previously, he only vanished. As for the boss itself, it is huge, taking up most of the screen. However, it is still quite capable of sprinting around the screen, laying down webbing that slows your character down and spawning endless numbers of tiny spiders. Its only weak-point is its head, which is very small. Finally, you have to fight this thing twice, and the second time is immediately followed up with another boss battle.
 * The second form of Sir Sweet in Prinny: Can I Really be the Hero is one of the few bosses with a reputation for literately inflicting physical pain on the player themselves. Does not play by the rules of boss fights meaning that you have to fight a Nintendo Hard boss without being able to stun him by wailing on the attack button for two and a half minutes per life, and you will lose a bunch. About as painful as the micro wave chamber.
 * Direct from Ren and Stimpy: Veediots is the "battle" against Ren at the end of the Stimpy's Invention level. You have to simply toss the Happy Helmet onto Ren's head to finish the level, but you are given no indication on what to do, and trying to throw the helmet at Ren is a challenge in itself. The helmet can barely reach the platform Ren is on, and if it goes on the platform but you miss him, it will get sucked into a tube and brought back down to your level, allowing you to try again. There's also two floating platforms, but you can't reach them, and they're no help at all, since the helmet slides off them almost instantly. To add insulf to injury, all Ren does is pace back and forth randomly at the top of the screen, saying "You eediot!" over and over again.
 * People who have played Toy Story for the SNES (or the Sega Genesis or the PC) will often comment on their nightmarish encounter with The Claw. This is officially when the game gets hard for some. Basically, you have to use Woody's pull-string to throw squeaking alien toys at the Claw before it carries Buzz off. It's harder than it sounds, particularly on the SNES, where the hit-detection on the aliens is weird. Also, you have to survive about five or six of Sid's coins before he "runs out," and Buzz gets closer to the edge each time. (Mysteriously, the storyline tells us that he has managed to capture Buzz and Woody between levels).
 * On the Genesis version, the aliens are easier to hit -- but there's this random swinging cable that you have to keep avoiding.
 * Carabs, the Stage Four boss of Astro Boy Omega Factor. The SHMUP sections of this game are similar in ways to a Bullet Hell, except that Astro Boy's hit box is twice the size of a standard SHMUP vehicle. Carabs will take off half your life if you touch him, and he takes up two-thirds of the screen. Trying to dodge through him is an exercise in futility, thanks to how dodging jams up in these sections. Oh, and if you try to fly under or over him, he'll change direction to slam into you. For extra fun, do this in the all-damage-doubled Rebirth mode!
 * Graffiti Kingdom: Most of the bosses are pushovers, but then you run into Telepin. He floats, dodging a lot of the faster physical attacks, spins around the arena making the Most Annoying Sound, can block, possesses six weapons that can combo about half your health bar off, and fights you in an arena that creates large explosions in short intervals. He's not even a Wake Up Boss; The boss after him is much easier.
 * The Wii One Piece games have the battle with Gecko Moria in Unlimited Cruise Episode 1. He spends the majority of the battle running away from you, which makes dealing damage very difficult. As he flees, he consistently launches annoying shadowy projectiles. It gets worse after you manage to bring him down to half health. He begins frequently abusing his super, Shadows Asgard, an annoying, almost impossible to avoid attack that given your levels is an instant kill for whoever it hits. Luckily you have nine characters to use, but the fight becomes a race to catch up to and deal damage to the boss before he murders everyone with Shadows Asgard.
 * The Legendary Starfy the final stage of the final boss, which is literal button-mashing so fast the only way I've heard of that could CONCEIVABLY work is to pause the game and put it down when you get tired. Oh, and you do this TWICE. Smouldering hate.
 * The Captain from Henry Hatsworth in the Puzzling Adventure is widely considered the hardest boss in the game. The sea dog himself isn't really a treat as he's a senile, decrepit old geezer in a wheelchair, the real menace is his hulking monster of a nurse who uses him as a bludgeoning tool. Not only the nurse's attacks cause a lot of damage and are tricky to dodge but she can also pitch capsules that will hatch into monsters. It becomes even worse in the last phase that takes underwater, where both the captain and his nurse become temporally invulnerable and you have to dodge them while taking care of their minions until you building up your Super Meter and unleash Tea Time to finish the crazy old man. The icicles that tend to rain down right before that phase and temporarily make columns unusable should you let them reach the bottom screen certainly didn't help.
 * The Machine is infinitely more frustrating. The Captain doesn't have a One Hit KO that he busts out extremely early in the fight, for one, and another that he spams later on. The Bait and Switch Boss beforehand didn't make things any easier, either.
 * In the higher difficulties of Iji, especially Ultimortal, the second Asha fight, in Sector X, is generally considered the single hardest boss of the game, and being the main obstacle that stands between people and Turbo Mode/Null Driver/Sector Y. Few people are capable of beating the second Asha fight in Ultimortal difficulty without the use of the Checkpoint.
 * Basically, the reason it's hard is reaction time. He has about 10 different attacks, and each has one or two ways to avoid it, but will always hit you if you're still. The problem is that you've got a window of generally about 0.2 seconds to see him appear, notice what position he's in and hence what attack he's going to perform, and start your dodge before it's too late. And he teleports around like crazy between attacks to confuse you, and fake images of him start appearing halfway through the fight. From 7:43 onward this video shows the problem very well.
 * Also from Iji, Proxima on the higher difficulties. This robotic boss can unleash a ton of attacks at once, many of which are very difficult to dodge (or else dodging one will get you hit by another), and unless you have very good weapon stats (which are not available on Ultimortal anyway) the only way to beat it is to hit it repeatedly into an electropod. The catch is that you have to wait for it to recharge, an increasingly long time with each difficulty, and during that time there's nothing you can do but try desperately to survive.
 * Any boss after Round 2 in Bonk's Adventure, they're such cheap bastards you're almost guaranteed to lose a couple lives. And worse, you have to fight a Boss Rush of the first four bosses in Round 5.
 * They're all pushovers... except for that fnarking Ballerina... THAT FNARKING BALLERINA!
 * Captain Cook in Bonk's Revenge. The Climax Boss of the game, he is a large leap in difficulty from first three bosses. This is the first boss to have two forms, and his second form is a big pain in the neck; you have to wait until he moves to his lower position(and shoots a deadly fireball) to jump onto and hit him, which is easier said than done without taking damage, and his attacks take off a at least a full heart with each hit.
 * Reapermon in Digimon Rumble Arena. The final boss of the game, and clearly designed to be the cheapest bastard on the face of the planet. His triangle attack results in two hits that cause your character to flinch, making you completely unable to avoid the ten-hit rush that immediately follows. Just to top it all off, he can (and will) follow it up with his flame attack, in which he causes a gout of flame to rise up from the ground and hit you another eight or so times. The worst part, however, is that this sequence of eighteen to twenty hits in three seconds will daze your character--leaving you stunned and completely defenseless against the same combo. Which inevitably leaves you dazed once more, allowing for a permanent stunlock until dead. Projectile spam is one's best bet--so help you God if you're playing a short-range character like Wormon for the sake of unlockable characters.
 * Ninja Gaiden: In the Xbox games, pretty much every boss is That One Boss for somebody. Special mention to Murai in the first game. He's the first boss in the game and a good number of people need help fighting him. He can block your attacks, dodge your magic, dash attack like you can, combo you for massive damage, and grab you (which is unblockable).
 * Alma from Ninja Gaiden Black. Alma is the queen of That One Bosses, the That One Boss from which all lesser That One Boss sprang.
 * Pretty much all of the bosses that force you to use the bow also qualify, if only because it's quite the change from being able to use Ryu's melee Hyperspace Arsenal.
 * Ghost Doku's backup on Hard Mode (where every boss is accompanied by some Mooks that get reinforcements every time you damage the boss) is especially annoying, as the Nunchuks are ill-suited to fighting him, but the only thing that can effectively kill the ghost fish. Waiting him out and hoping to outlast him by burning through your Elixirs of Spiritual Life is also not an option, as he can drain your health.
 * The three NES Ninja Gaiden games had many tough bosses, but the worst was probably in the first game, because his fireballs were almost impossible to dodge, and losing against him sent you back three levels. Getting to him with an Air Slash was the only way most people beat him.
 * If you're playing single player on Professional difficulty in Resident Evil 5, be prepared to face hell against Wesker . This is mostly because Sheva LOVES running off to get killed, on a difficulty in which 1 hit sends you into Dying status. The only way to beat Wesker on your own here is to bring a rocket launcher and pray you can hit him with it, which tends to be ridiculously hard to do.
 * Ndesu, aka The El Gigante of Africa. You are caught in a truck that you cannot move, and the only way to not be hit is to A. shoot him enough so that the attack is disabled (ala House Of The Dead, but without the helpful meter), or B. hit the action commands that come up for a half-second. Chances are, you're gonna get the A. part in spades, until he pulls a giant boulder out of the ground, which you need to shoot before it hits you, otherwise that's a massive chunk of your health. For the B. part, chances are, cause the weapons you get are a RPK (don't ask why UN/BSAA troops are using an RPK. I don't know.) and a minigun, you're gonna be busy firing, and if you hold over, and THEN try to hit the action commands, you fail it. Also, random enemies like to come in at about the halfway point, and shoot you with the flaming arrows, and did I mention that you can't heal yourself if your health is too low, because you're in a TRUCK?! THIS IS A HALFWAY BOSS, FOR GOD SAKES!
 * No matter how bad that boss is on the console version, the PC version is much, much worse. The keyboard action commands are very poorly located, and a lot of keyboards won't detect the buttons properly anyway.
 * The fights with Nigel Bloch in Agent Under Fire qualify. In the first one, you're on a tram rail with no cover. There's a wave of guards then Bloch comes out on the platform of the central control tower. He has perfect accuracy with his weapon, even while recoiling from being shot. Then he opens up the doors below to reveal lava that slowly damages you in a subversion of Convection, Schmonvection. You have to take out another wave of Mooks, then use a video guided rocket launcher to take out three lights above. Go too slow, miss, or take too much damage in the fight and you gotta start all over from the beginning.
 * Ace Combat gives us a few examples:
 * Zero: The Belkan War has Alberto "Espada One" Lopez. Don't laugh at the fact that he's "only" piloting a starting plane, for he can be very hard to hit and can outmaneuver Bigger Sticks quite easily. Real horrorshow, that one.
 * X: Skies of Deception gives us Alect Squadron in Fenrirs. Think Alect Squadron in "only" S-32s was tough? Think Fenrirs with relatively nooby pilots were challenging? Try them together. In addition to being fiendishly agile, their Invisibility Cloak meant that you could be fired on from seemingly nowhere, making dodging difficult, and you couldn't get a stable lock-on since the lock would break every now and then, so even QAAMs had rather reduced performance. You did have the option to destroy the generator powering their invis, but that did not affect their lethality. Fortunately, once you did defeat them the rest of the mission was, even objectively instead of relatively speaking, easy.
 * 6: Fires of Liberation graces us with Ilya Pasternak in his cluster missile-hurling Nosferatu and a bunch of small drones that are pretty damn hard to hit. On top of the cluster missiles attack, the Nosferatu is also capable of monster acceleration and a dime-sized turn radius which allows him to dodge a missile whenever the fuck he wants. So on higher difficulty levels, the fight consists of Ilya launching the missile swarm, and then hauling ass roadrunner style. Meanwhile, his numerous ridiculously agile drones keep you from achieving a lock quickly and fire their pea shooters at you. By the time you do get a lock, he's already turning for another pass at you.
 * Joint Assault: . Since he's using a superplane, crazy speed and agility are a given, so that's not why he's here. There are other reasons - He has a rear-facing machine gun that shoots down missiles at his six, so you have to somehow get in his face to hurt him if you can't use guns reliably. If you can, he goes into a second phase where he does bullshit rolls to dodge missiles; Naturally, you can't do any such thing. Hurt him enough now and he goes into a third stage where he suddenly becomes a lot more aggressive. A lot more. To make matters worse, he'll eat as many missiles as you needed to kill the other three guys combined and keep going. Piece of shit.
 * Queen Bee from E.V.O: Search for Eden. She's a much nastier version of the King Bee from earlier in the stage, and he was pretty unpleasant.
 * Hell, Birdman King too.
 * Then there's Cro-Maine, who can hit you off the screen (and the attack HURTS, too)
 * FUCKING Nephtis in Zone of the Enders: The Second Runner, first off, none of your weapons damage her, the only way to damage her is to knock Nephtis into the surrounding scenery, this becomes most grating after the train sequence, where you're inside a cylindrical room with multiple levels, and nothing to grab onto to use as a suitable projectile/defence. With fricken Clods all over the place which not only try to grab and hold you in place while Nephtis does its kamizake run, but they confuse your lock-on function, in which adding to Nephtis' unpredictable flight path, makes it impossible to lock onto to the damn thing until it's too late.
 * Gets even worse in the fight after that, when  and you have to beat it without actually damaging it. "Cross swords and grab! Cross swords and grab!" How about...FUCK YOU?
 * Most bosses in Konami's arcade run and gun, Sunset Riders, have fairly easy patterns to deal with once you figure them out. Chief Scalpem (renamed Chief Wigwam in the SNES version) is not one of these bosses, as his pattern involves jumping all over the place and throwing knives freakin' everywhere. Next to the final boss, he's the hardest boss in the game, and the final boss is only hard because he takes an ungodly amount of bullets to kill, not because he has difficult attack patterns. As an added "fuck you" by Konami, he's also the one boss that you don't even get the pleasure of finishing off, as his cute little sister runs in and begs you not to kill him.
 * Bomberman has it's fair share of incredibly tough boss battles...
 * Bomberman 64 has two tough as nail bosses, Mantis, a a 30ft ice-crystaline spider and Cerebus, Altair's High-Tech Mecha guard who's destined to turn anything into a big crater.
 * The fight against Mantis will first start off in her cave, in which the floor is incredibly slick and difficult to maneuver around. She happily enjoys jabbing you with her enormous mantis-like front legs (and even jump up to attack with both), climbing along the walls to spit out baby-spider-like things, and sliding herself into you. However, the battle really goes hay-wire when you've damaged her life meter to halfway, she breaks the floor and drops you down to her web, in which there's a good chance you'll miss it and fall to your doom. Considering she takes up a good portion of the screen, if you don't fall to your doom, you still have the possibility of doing so because you walked off the web, all the while she still tries pick and prod you to death. If you do fall and you haven't collected the 100 gold cards yet, Sirius will come to help you up, but upon collecting all the gold cards, you'll just fall and die.
 * The fight against the Cerebus is insanely difficult because the fact that all his weapons have an enormously wide and short range, and the room you fight him in is very small and enclosed. His machine gun fire is pretty easy to avoid, but his homing missiles from his two primary canons and his smaller homing missiles from his container "shoulders" (it's a hovering robot, mind you) can and will force you into a trap. What's worse, if you haven't destroyed his arm canons and you hang alongside the wall too much during his attacks, he'll do a back-flip loop with enormous laser blades and try pulverize you into the wall with a mighty whack. There's also another attack he uses that creates an odd light glow in the middle of the room that slows you down, but allows him to keep moving at an insanely high speed, and walking into that light will cause you to die by shrinking out of existence (however, you can get a gold card if you kick a bomb into and also disable the beam). Add all of this into the fact that he dodges all bombs kicked at him and that this is only the "normal" level of gameplay (hard is much worse), and you pretty much have the ultimate "high-tech harvester" as the name of the battle implies.
 * The Nintendo 64 game Nightmare Creatures has the Sewer Snake as the very first boss. This snake has five heads which shoot out bursts of flame at ridiculous speeds as its first stage attack. This means that your character is going to be spending a LOT of time lying on the ground while engulfed in flames. The second stage (should your character survive the inferno long enough to knock down the five support beams) is spent trying to attack the heads of the snake as it moves around the fighting area. Did I mention that this is the first boss fight?
 * The giant vampire boss from Horror Island, the third level of Rainbow Islands. It was infamous in its day.
 * Think the Wii version of A Boy and His Blob looks cute? You'll be changing your tune hardcore after you encounter The Beast at the end of World 2. You have to lure him close to you, create holes in the ground, and let airborne mines drift down to blow up on him. Sounds simple, right? Except that, while the Boy and Blob toddle around at an appropriately little-boy-ish pace, the Beast is lightning fast, vicious, and so friggin' huge that even the highest platform in the arena isn't safe from his horrible back tentacles of oozing DOOM. You have a literal safety bubble, but can't use it and the hole you need to defeat the boss at the same time. Even the developers themselves said he was too hard!
 * Alien Soldier. Being a Boss Game, there was bound to be at least one of these.
 * Epsilon-1, the main character's Super-Powered Evil Side that somehow manifested into an evil Humongous Mecha eagle bent on destroying humanity. Its weak spot, the head, was blocked by its two damage-absorbing talons, making it hard to squeeze in shots. Secondly, the only weapon effective against it was the Lancer which did huge damage, but each shot cost a TON of ammo. Worse still, you might have probably run out of ammo for it after a Boss Rush consisting of three other bosses, two of which were not exactly easy. Thirdly, EVERY SINGLE ONE of Epsilon-1's attacks did 200 damage to you character (enough to kill you in say, 4 hits). The only saving grace you had against this fiend was that it was one of the few bosses that did not do any Collision Damage to you.
 * Azetlor on the Play Station 3/360 versions of Ghostbusters The Video Game is a real nasty piece of work, particularly on Professional Mode.
 * The Shadow Bros from Vista Quest are a real wake up call after the first boss, being the cakewalk he is.
 * Every Armored Core fan worth their salt will instantly recognize Nineball, who has become an Ensemble Darkhorse for the series for this very reason. It helps that he has an incredibly badass theme.
 * Rimfire from AC:Last Raven. Savvy enough to come immediately after a weaker boss, he's got 2 back mounted-chain guns, and duel wielding 4 barreled machine guns. He'd be a "Wake-Up Call" Boss if every other boss wasn't nearly as bad.
 * The Stage 4 boss in the original Contra. Spams homing projectiles that increase in frequency the longer you take, and its weak points are only vulnerable for a split-second at a time. If you lost your Spread Gun, you're more or less screwed.
 * The final boss from Eureka Seven Vol 1: The New Wave is just plain evil in both forms. Your first fight is against him on the ground while you pilot the Nirvash, the absolute worst LFO or KLF for this battle since it has no weapons and he has an 8 pod missile launcher and he hits just as hard as the Nirvash does. Your only defense is your excellent offense and your boomerang which are both pointless against his massive forefront blasts. The second part has you battling him in the air during lift combat which up until this point you had been in only one other one: The training Session for lift combat several chapters back.
 * Nearly all of the boss fights from the first Rayman are pretty hard, but some of them just take the cake. Perhaps the best examples include Space Mama and Mr. Skops; Space Mama dishes out a merciless assault of fast, hard-to-dodge attacks while Mr. Skops has a homing attack that is nearly impossible to dodge. Also, one part of the Sequential Final Boss fight is ridiculously hard, especially when compared to the rest of the phases—including the final one.
 * The Oni boss from Muramasa. You need to hide from all of its attacks, otherwise, kiss goodbye to approximately 4,000 health on Muso (Normal). Sure, there are rock piles for you to hide behind. But then there are all the little demons that, while they don't do any damage, cause you to stand up and reveal your hiding place. And the way the controls are set up, attacking makes one travel out from behind. Oh, and the boss can knock over your hiding places. Given that even without grinding you have about 6K health at this point, still...lots of healing to be had. And if you haven't gotten around to buying some of the higher-ranked healing items, this can take a while...and you'll likely get picked up again. Oh, and it has a health upgrade from the previous bosses.
 * The Dual Boss battle with the Torturer and Deviant 1 in Soldier of Fortune II. Deviant 1 attacks with a sniper rifle, while the Torturer is Made of Iron and armed with an instant-death M60 machine gun, and there's almost nowhere to hide.
 * The Typing of the Dead has the boss of Chapter 3, Tower. For the first phase, you are given a question and 3 answers; answer correctly and you damage it, answer incorrectly or take too long and you take damage. However, some of the questions can be confusing to answer and you don't have a lot of time. Then comes the second form, in which Tower's last head swims or burrows around and you have to type the phrase shown before it bites you. If you're in the pool, you have plenty of time, but if you're in the sand pit it's harder because the phrase doesn't show up until after the head surfaces, which leaves you very little time.
 * Then comes The Magician in Chapter 5. For the first part, you have to type its phrases quickly and without making mistakes. Miss and it's automatic damage for you. Then you have to cancel his fireball attack by typing 3 phrases in a short timespan before they hit you, and only then can you do damage to him.
 * The vampire from Severance: Blade of Darkness. A lot of HP, powerfull attacks, drains your life, teleports behind you and has a strong shield that deals massive damage to you if you hit. And you WILL hit it, since he has his guard raised most of the time. And you fight this bastard several times. If you go back to previous levels for One Hundred Percent Completion by collecting every Plot Coupon to unlock the Sword Beam on the Infinity+1 Sword he pops up as a Boss in Mooks Clothing several more times, with less health but still holding that frigging shield (which you never get to pick up).
 * Moles the walrus from Billy Hatcher and the Giant Egg, he first starts by ice skidding towards you which is easy to doge but then he rolls into a sphere of ice, and very rapidly starts bouncing around the room, and this attack is very unpredictable, also to make matter worse every time he hits a wall, small ice spheres appear and start bouncing around the room with him, eventually he will stop and allow you to hurt him but those ice spheres are still bouncing around, and while you're focusing on hurting him, those ice spheres can hit you, stunning you for a second, and he will repeat this process for the whole fight.
 * Dark Corvo is even worse, he uses shadow clones of previous bosses that you have fought, some of his attacks are extremely hard to dodge, for example his shadow clone of Glur shoots homing bouncy balls, his Saltim clone rapid fires bombs at you, which are a very hard to dodge, also when Dark Corvo clones himself and attacks you, he attacks at high speed, and there is no clue as to which is the real one, and if you don't hit the right one fast enough he will repeat the attack, it is especially painful that Dark Corvo comes after one of the hardest levels in the game. He's so hard that the game actually warns you how hard he's gonna be before you fight him, and this is a hard game!
 * While Marvel Ultimate Alliance is fairly easy, the Mandarin is an incredibly tedious and irksome boss fight. He spends most of the fight in secret rooms you have to access via teleporter. The problem is if you use the teleporter, the Ultimo will follow you in and pull you back out. The way to override this to get one of the exploding bugs into the teleporter with Ultimo so it explodes on him which is... difficult.
 * MUA 2 sics Magneto and Quicksilver on you AT THE SAME TIME.
 * Frogger Beyond has some fairly difficult bosses, but the giant flying claw completely stops the game right then and there. The battle consists of pressing buttons 1 to 4 in order, while avoiding its fireballs. Sounds easy? Not one bit. The first phase is so easy it's not even funny. Then comes the second phase, which is a huge leap in difficulty. Not only are the switches out of order, but there's a lot of missing spaces and moving platforms. Its attack is firing a row of fireballs in a single line, which can easily hit Frogger if the fireballs are in the line of a moving platform. The third phase? It's a borderline Luck-Based Mission. The buttons are not only out of order, but constantly move, there's less actual space and more moving platforms, and the claw gains a nigh unavoidable attack, an aimed cluster of fireballs (goes ahead of Frogger) that is, very difficult to dodge. Oh yeah, Frogger has one hit point, get hit once and it's back to the beginning. If there's one good thing about the boss, it won't attack when Frogger is on a platform.
 * The fight with Tyrant on board the plane in Resident Evil Code: Veronica. As usual, it's Made of Iron and a Lightning Bruiser, but this time, there's hardly any room to maneuver. There is also an element of Puzzle Boss where you have to use the catapult to throw it out of the plane after weakening it with your weapons, if it's not damaged enough, it will throw the crate back at you.
 * In the NES adaptation of Willow, you have General Kael. If you try attacking him from the sides, he'll charge at you, dealing significant amounts of damage. Attacking him from the front leaves you open to his sword, also dealing a lot of damage. Standing still will have his sword deflected off of your shield; using that technique is crucial to survive the fight.
 * The final boss, Greedy, from the Megadrive game Ristar. Oh so much. Let's check his three forms shall we?
 * At first, he refuses to even fight you, throwing up five, newly introduced and unique to this fight, teleporting mooks, which move in random directions and fire energy weapons in your general direction. They also move REALLY quickly. If the Random Number God is not in your favour today, this sequence alone can be an absolute nightmare.
 * When the mooks are disposed of, he finally rises out of his chair and... teleports. Constantly. Oh, and he's quicker than the enemies. Successfully hitting him will result in... Greedy spawning more enemies to deal with. Not to mention, if luck is not with you he will either dodge out of the way of your attacks, or summon a shield of mooks. This shield is thrown, one particle at a time, in your general direction. And don't think this doesn't work as a shield either, if you hit him whilst this shield is up, you are pretty much screwed. The shield is fully repaired, Greedy starts to teleport with the shield still up, AND he throws EVEN MORE enemies at you.
 * Of course, after a few hits, Greedy stops messing around, and the real fun starts. In his third form, he can now summon black holes, and fry the floor with lightning. Oh. And he's even quicker than before. Good luck getting through this fight unscathed.
 * The amoeba-like boss in level 17 of Arkanoid 2: the Revenge of DoH. It was an Unexpected Gameplay Change, where you had to hit the boss repeatedly with the ball, which would increase in speed much faster than it would on most stages, while it emitted a constant stream of enemies at all times - and yes, it could spit out an enemy right where the ball was about to hit it, acting like a shield. If that wasn't bad enough, it would randomly decide which enemies would be spat out every time the level loaded. If it decided to spit out those damn black spheres that couldn't be destroyed by the ball on this go and nothing but, you pretty much had to accept losing a life. Oh, and it recovered all its health if you died.
 * The Rattlecrab in Scaler - an Unexpected Shmup Boss, which is fought from a first person mode using Reppy, whose attacks only chip away at the Rattlecrab's health. What makes it worse is that you can't take many hits, health is extremely scarce (as in 'there's-only-one-place-full-of-hard-to-hit-cocoons'), and after a while the boss starts shooting out enemies at you which must be hit, otherwise you'll be brought down very quickly. And once you are, well it's back the start of the fight and chipping away health again!
 * Infamous has Kessler. While he IS the final boss, he reaches ridiculous levels of difficulty when playing on hard (for more reasons than just the difficulty being raised in general). His health is absolutely ridiculous (to the point where it has a checkpoint every 25%, and it can take nearly an hour to whittle him down all the way), and he dodges just about everything. Grenade hits are pure luck, and not consistent enough to be worth it. He automatically dodges missiles (your second most damaging attack, and best hope of killing him),and will charge you (followed immediately by killing you) if you try to get him with your Storm (though it can be used at one point in the fight when he summons drones. This is pretty much the only way to not die). So, you can only hit him with your basic lightning bolt. Bad enough as is. Add in the fact that he has SEVERAL attacks that will kill you instantly if you don't have full health or dodge, and a charging attack that allows him to evade your shots while rushing at you for an impressive swing.
 * King Fury in Okamiden. The first problem: he flies, so it can be difficult to hit him with a normal attack. Second: he's absurdly fast. Third: your partner has to spend most of the fight standing in front of a control panel and King Fury apparently knows he can only take 3 hits, because he specifically targets him over Chibi, turning the fight into an Escort Mission as well. But the biggest problem? Ink no longer regenerates. You have to counter almost every move King Fury makes with one or two brush techniques, and if you're lucky, you can hit him maybe once or twice every time you knock him down. This means it takes a lot of ink to do a little damage, so you'll probably run out of Spirit Ink before long. And then you get him down to half hitpoints, and he summons a clone.
 * Viewtiful Joe had Another Joe. An awesome boss in his own right, he has a knack for killing you without breaking a sweat. One of his attacks can decimate your health if you're unprepared for it, and if you run out of VFX while fending it off, your death is guaranteed. Made doubly frustrating as you end up having to fight him a second time at the end of a mandatory Boss Rush.
 * Another Joe? Seriously? His boss fight was fun - you could even knock him into the electronic pits to damage him, and the fight was a hell of a lot easier if you had Voomerangs. Fire Leo was HORRIBLE.
 * To elaborate, Fire Leo was the final boss at the end of the above Boss Rush. His battle involved you using a shitload of Mach Speed to set YOURSELF on fire so you were immune to his fireballs (temporarily), rushing after the free-running bastard and pummeling him until he either jumped back into the lava surrounding the platform, or he decided to do his ridiculous ballerina twirl claw attack. Said attack gives you very little warning before he strikes (on harder difficulties, you get no warning whatsoever). Also, he runs around the platforms spewing giant rocks that will hurt and temporarily stun you if they land on you. The same rocks you have to punch to avoid being set on fire.
 * The Stage 24 boss in Bleach: Soul Carnival 2, a pair of Menos Grande. One of them will invariably teleport right on top of you at the start of the fight, and getting hit by these guys sends you flying. It doesn't help that half the ground you can fight these behemoths on is quicksand, which does damage if you're stuck in it long enough. Additionally, your regular attacks do naught but 1 point of damage to them, forcing you to rely on special attacks. And if you get caught in between them while they Beam Spam, but can't hit both of them at once? My condolences.
 * Before them, however, there's Hollow Ichigo in Stage 21. Hollow Ichigo is fast as hell and can do anything you can do...with one exception: He can use a Burning Attack and you can't. One that takes up the entire screen and deals an ungodly amount of damage.
 * Speaking of Dual Bosses, there's Ikkaku and Renji at the end of the first Challenge stage. If Ikkaku's long spear combos don't drive you up the wall, then Renji's homing sword-things will. And if that doesn't get you? They will invariably activate Bankai, sometimes simultaneously. In this state, their attacks get ridiculous range and priority, and even a Burning Attack won't so much as stagger them. It does damage, sure, but it doesn't stop their relentless assault.
 * The Cores and Turrets Boss in Stage 3 of Journey to Silius fires a complex pattern of lasers and bullets, making it much more difficult than other bosses, since you have to jump through the hail of fire to hit the core, and you are probably low on gun power at this point.
 * In Jersey Devil, The giant octopus fought at the end of the "Monkey's Trail" mission is quite possibly the hardest boss in the entire game. At first, you can't hit him and can only see him swimming outside. Once you figure out how to draw him into the room, all hell breaks loose. You see, there is one large hole in the center where the giant octopus' head come in and eight more smaller holes around the room for its tentacles. The tentacles can reach you anywhere in the room, no matter what! Oh, and good luck trying to dodge them while picking up TNT boxes to hit the boss with, for if you get hit, you will automatically turn to face that tentacle and throw the TNT box in that direction if you happen to be holding one at the time. You're practically destined to lose at least one or two lives during this fight.
 * The underrated Survival Horror/stealth game Siren had two outstanding Made of Iron marathon bosses:
 * The Final Boss is much easier to beat if you're not going for One Hundred Percent Completion. If you are, then you don't get to use the special item that calls a meteor down upon  to kill it off. You can only use it twice, and must use a special sword to finish the battle. Unfortunately, being the type of game that it is, melee combat is very awkward, and since the Final Boss flies above you at all times, you have to aim up to hit it with the sword. This battle seems to take forever; it's possible that enemies regenerate health in this game.
 * Takeuchi's interminable fight against . It's an incredibly long and difficult duel between Takeuchi, who only has a pistol, and , who has a rifle. It takes place on a small battlefield where you can mercifully take cover if you need to regenerate your health.
 * from Prototype, especially on Hard. Holy hell. For starters, he has a truly ridiculous amount of health, so much health that the game hands you tons of 500 pound bombs and aircraft to throw at him, and it still barely hurts him. Rocket launchers and helicopter missiles are next to useless against him, but apparently no one told the soldiers on the USS Reagan, because the entire time you're fighting him there are explosions slamming into both of you. He can take it fine, whereas you get knocked around and have huge amounts of your health taken off. The boss's attacks are all extremely damaging, and at least one of them is unblockable. However, the worst part is the goddamned time limit, which is ridiculously strict. You have to execute everything perfectly to defeat the boss in the tiny amount of time you're given. If you are hit by two rockets or one of the boss's attacks over the course of the fight, you may as well start the fight over, since you just wasted too much getting up from the knockback animation and your character (along with New York City) is now
 * Ratchet and Clank:
 * Chairman Drek from the first game is infamous for how hard he is. Many people say they had to buy the BFG of the game series, the RYNO, to beat him without losing their sanity.
 * Dr.Nefarious in the third game can be a real challenge the first few times around, especially if you haven't leveled up your weapons enough.
 * Spanky's Quest is a game that runs on Hard Levels, Easy Bosses, save for the Grape Boss. He relentlessly chases you in a spiraling pattern that isn't too hard to dodge at first, but then he throws his individual grape minions at you, who move quickly and attack three at a time. Jumping over them while making sure you don't crash into the main cluster of grapes is a daunting task thanks to Spanky's movement being a tad slow and floaty, and the aggression of the main cluster and his minions can make hard to safely get a hit on him.
 * Giaguaro, the legendary panther from Red Dead Redemption 2. What makes him this compared to the other Legendary animals is the fact that he'll track and hunt you like normal panthers, which are Demonic Spiders to begin with. He's hard to see thanks to the way he blends in with his environment, and if he's able to pounce on you there's no fighting back. You die automatically.
 * Warframe has a few examples:
 * Counselor Vay Hek, a flying bullet sponge with completely random movements, fully invulnerable except for a tiny weak point that's revealed only when he buffs his soldiers, a machine gun of his own and an unavoidable attack that always applies a magnetic debuff, weakening your shield and draining all your energy. He has a second phase when weakened enough, but taking a different form that's fully damageable and is much easier to hit. The fact that he flies away when he loses rather than dying like other bosses adds insult to injury.
 * Mutalist Alad V, invulnerable unless he uses one of his special attacks, leaving shorts openings, not helped by his shield that may fully recharge between two openings and the constant swarm of Infested coming from every direction and hitting hard when they get close. Without some high burst damage to punch through his shield or toxin damage to bypass it, this fight is nearly unwinnable. Also noteworthy is his ability to mind-control players and turn them back on their allies, some warframes being capable of healing him to full or wipe out their entire squad (solo players don't have to worry about this, fortunately).
 * While Five Nights at Freddy's: Security Breach doesn't exactly have boss fights in the traditional sense (save for Monty, sort of), your first encounter with the Daycare Attendant's Moon form is a tough (and terrifying) one. You have to run around the pitch-black Superstar Daycare and restore power by finding five generators and turning them on. The problem is that they're scattered around a confusing, maze-like playplace, and Moon is a Super-Persistent Predator who blends in with the darkness of the daycare and can ambush you from surprising angles thanks to his ceiling-mounted wire giving him free range of the place. You can distract him by knocking over stacks of boxes to trigger his Neat Freak tendencies, it doesn't do much to help when you're trying to find that Last Lousy Generator.