That One Boss/Action Game



This page is for venting on bosses that gave large numbers of people grief. They do not need advice on how to beat them. They already know how to find GameFAQs.

The page isn't for you to talk about how great you are at the game either. Save that for your blog.

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

NOTE: Bonus Boss is completely banned. They are supposed to be overpowerful and have no real standards.

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 Draculas 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 Draculas 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

 * In the first Crash Bandicoot game there was N. Brio, who had the most health of any boss in the game, even Neo Cortex. He starts by throwing exploding chemical fillled beakers at you which you havbe to dogde, 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 was to was to dodge the falling debris, stand on top of it, and wait for him to charge at you so you you could jump on top of his head. You had to do this this several times before he finally gave up, and due to the difficulty of this fight, it almost put Neo Cortex straight into Anticlimax Boss territory.
 * The second Crash Bandicoot game had N. Gin, who had a powerful spaceship you had to destroy by throwing Wumpa Fruit at it. It didn't help that the ship took a huge amount of hits before it lost one part of its health bar, and all the while you had to avoid massive amount of lasers, missiles, and other nasty projectiles while you were 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.
 * The third Crash Bandicoot game had N. Tropy who could use his time powers to shift the position of the platforms you were 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 took 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, yes even more than Neo Cortex, and will continue to Beam Spam, shoot missiles, and 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.
 * 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. Also, be careful because when you do succeed in killing them they somehow respawn the next day and can really catch an inexperienced player off guard because of that.
 * 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 on the True Eye cult is also deceptively difficult. You'd expect him to at least be slow due to his old age, but nope, he'll rocket after you at a surprisingly quick pace and beat you senseless. His sword also has a great amount of range, and not to mention that thing's strikes hurt.
 * Among the story bosses, Isabela Keyes is easily the worst of the lot. 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 take too long in fighting her, 7:00 PM rolls by, and thanks to the transition cutscene showing the zombies growing more violent, she'll disappear and you lose the fight and will have to start the story mode all over again. Keep in mind, this also happens if you leave the area for whatever reason.
 * 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 inflicted on you. He's a quick shot and very accurate, so your best bet on beating him is to forget about shooting back, just chug a Quickstep, rocket on over, and beat him senseless with a good weapon.
 * 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 fry pan. He also is 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.
 * According to the devs of Off The Record, they actually toned down his difficulty for this release.
 * Brent Ernst, 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. 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 was fast and had an erratic movement pattern. She had a good amount of health, and when she took enough damage, she Turns Red and becomes even faster and much more erratic which meant you had to have quick reflexes to defeat her.
 * King Zing Sting 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, and also keep in in mind that you have to climb up after him when he flies away to higher ground and dodging 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, and 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 Queen Urchin, 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 infinte amount of her children, the regular enemy urchin 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 in the final phase is to hit the small urchin at the wall so they bounce into her and stun her temporarily, allowing you to hit her while she's unguarded, and you must hit her this way twice out of the six hits it takes to defeat her, and 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.
 * Donkey Kong 64 brings us Mad Jack and King Kut-Out.
 * Mad Jack just looks pants-wettingly terrifying, and that's not the worst part; 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 can jump 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.
 * King Kut-Out is a cardboard 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 him/her 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.

Kirby

 * Kracko in Hard Mode in the original Kirby's Dreamland. Lightning fast, with a completely different attack pattern that gave you next to no time to react. Of course, getting to him meant first getting through Kaboola, who was a pushover in the regular game, but in Hard Mode became the most insane, random, frantic battle in the game. Beating Kaboola on Hard was as much luck as anything else.
 * They tried to replicate the difficult of fighting her in the Kirby Super Star Ultra game for the DS, but nothing can compare to the original. That thing is a MONSTER.
 * 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...
 * Kracko doesn't appear in Kirby Squeak Squad. Oh no, that would be far too easy. Instead, you fight Mecha Kracko. 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' Adventure and its remake. Being a fairly unpredictable quick target that many abilities don't work will do that but not to everyone. Canvas Curse Paint Roller 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 matches to get all the collectables are hard to complete, much less with a grade a score.
 * Meta Knight is extremely difficult to defeat, especially on Extra mode, due to the fact that you can only use the Sword against him. Little else in the game measures up to the difficulty of this duel.
 * Galacta Knight is pathetically easy when fighting him with Metaknight, due to Metaknight's healing move, Mach Tornado, and overpowered moveset. Then comes the fight with Galacta Knight right next to the True Final Boss 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.
 * 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.
 * 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 (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, four times to KO, or using Beam or Spark. – 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 strength hits to get 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: Titan Head. This 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.
 * 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 because he usually will jump out of the way of it, 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.
 * The Metal General on EX mode from Return to Dreamland is this for many, due to an unexpected event during the fight. He starts out as a buffed version of the regular mode fight, like all the other bosses, and everything seems fine and dandy when you beat him... Until he suddenly gets a gigantic robot. While it is easy to dodge once you get the hang of it, it WILL throw people off guard. Also, guess what? Once you do beat it, yet another form pops up. It's 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.

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 as well. 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.
 * Wart is pathetically easy to fight as Luigi, and even moreso as Peach. He's still not too tough to fight with Mario, but if you're playing as Toad? GOOD LUCK. Thanks to Toad's crappy jumping skills Wart is next to impossible to cheese by super-jumping behind him and attacking from there, meaning that you basically have to grab a vegetable and toss it into his mouth with perfect timing before the bubbles he spits destroy the veggie. Even worse is that his bubble storms coincide with the vegetables popping up quite frequently, meaning that you must possess split-second reflexes to grab a veggie without taking a hit.
 * Wendy Koopa. In Super Mario Bros 3, the female Koopaling is the worst. While the others' attacks will fly offscreen, the rings of energy she fires will bounce round the room endlessly, as she continues to add more. If you can't stop her before there are more than three or so, you're not going to.
 * Give Wendy a shot in New Super Mario Bros Wii too. Essentially the exact same fight, but underwater, meaning that for a good portion of the fight, you can't stomp on her thanks to water physics!
 * Also from Super Mario Bros. 3, her big brother Lemmy also proves to be quite difficult. Like Wendy, he spawns projectiles (circus balls this time) that don't respawn, and he teeters around on a ball making not only his movements awkward, unpredictable, and somewhat hard to counter, but you have to jump pretty high to hit him which can mean that you'll likely get whacked by a ball. He wouldn't be too bad normally, but thanks to his Airship being one of the game's nastier ones, you're likely to fight him after losing your power up outside.
 * Roy is also tough, mainly for introducing a new battle gimmick in a rather nasty surprise: Roy is one of two Koopalings (the other being big bro Ludwig) who cause the ground to shake when they land after a jump. If you're on the ground when he lands, you're a sitting duck since he'll waste no time in hurting you afterwards meaning that you have precise timing in dodging the quake-jumps. What truly makes Roy count as opposed to Ludwig is that his airship is quite tricky to get through, meaning that like Lemmy you'll likely be fighting him after being reduced to your One-Hit-Point Wonder form.
 * Luigi's Mansion has Boolossus, the game's third boss who seems simple enough on paper: you pull the enormous Boo to aunicorn 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. Super Mario Wiki says there are 64 little mantas you have to vanquish. Even worse, when there are only a few left, they turn pink and actively chase you. Even worse, when going to refill FLUDD, you'll find some of the water pools are electrically charged.
 * To be accurate, the moment all mantas left are the tiny ones that you can actually kill, they will start chasing you. 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 hit 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.
 * Super Mario Galaxy had one in Bouldergeist. While seemingly easy he had attacks that blocked your paths, regenerating body parts, shot rocks at you constantly, and the only means to destroy it was to use stuff he threw at you that would explode if hit or held too long. If that wasn't enough, he also took twice as many hits as any other boss in the game besides the final one. His only saving grace is that occasionally he'd shoot some health at you, but that did little to comfort players looking for one hundred percent completion who had to undertake a no damage run on him. And when the Daredevil Comet came into play, those coins that he throws at you vanish, which makes him the hardest boss in the game.
 * 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.
 * Although most of the bosses of Super Paper Mario are relative pushovers (especially when compared to some other examples in the RPG predecessors of the series), Mimi can give people a major headache the second time you fight her in Sammer's Kingdom. She's even worse the third time you fight her. First, she crawls on the ceiling and spits out Rupees. You need to pick one up and hit her with it from below, then jump on her. Easy enough, right? Well, this process has to be repeated eight times. You have a very small frame of time in which you can jump on her, and if you don't do it in time, then she starts throwing the Rupees, which are much harder to dodge. Though you can hit her while she's doing this, it's a lot tougher to do, and defending will be your highest priority. Each gem does 4 damage per hit, which really adds up. Even if you're good at avoiding damage, it's a very time-consuming fight that will likely leave you wondering just when the hell she's gonna die.

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.

The Legend Of Zelda

 * The Legend of Zelda:
 * Gleeok, a hydra monster found in three dungeons. The other bosses are pushovers, but all you can do against Gleeok is stand your ground and hope you have a potion left.
 * Gleeok returned in Oracle of Seasons, as did a bunch of other bosses from the original, but in OoS, he wasn't the only boss that could try your patience. Digdogger was especially annoying because you have to fight it by using 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--and Manhandla, a four-headed Piranha Plant that you have to fight with the Magic Boomerang, the most frustrating item ever devised for this series.
 * Manhandla's first incarnation was the boss of the third dungeon in the first game, and at that point you would normally have five or six heart containers, and each hit takes off one full heart container, its constant fire balls and quickening movement means it will be very annoying, if you don't manage to kill all four heads with your first bomb. The later ones aren't quite so bad as you should have a new sword and more hearts by then.
 * The Legend of Zelda a Link To T He Past:
 * Mothula holds the title in this game. Erratic movement, randomly-changing conveyor floor, randomly moving blade traps, and a three-beam attack that's hard to avoid if you're trying hard to avoid 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).
 * 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.
 * Moldorm should definitely qualify; he's unlikely to kill you, with the numerous health powerups and fairy fountains near him. No no no, he'll just knock you off the platform with his oversized head, which restarts the battle and returns him to full health. Meanwhile, you have to hit his (much smaller) tail, which he can actually reach with his head. And his movements are very difficult to predict, so 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.
 * Blaino from The Legend of Zelda Links 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, That One Boss is Dark Link. 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.
 * 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 Legend of Zelda Majoras 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).
 * 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.
 * Fighting Goht, which is a combination of Chasing Your Tail and 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. Although by the fifth time around, you forget why he was so hard the first time. However some people find it very easy to avoid taking damage, the fight just takes longer that way.
 * The Legend of Zelda the Wind Waker:
 * Gohdan is That One Boss. He is, after all, 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 you have to fight him 3 times, with him changing his pattern each time! Especially with the fast third form, an Expy of Moldorm from A Link to the Past,where you have to hit it's tail with magic-depleting Light Arrows without the luxury of L-targeting. And especially the third form. 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 the Snake often can't touch Link. The trade-off is the tail becomes more difficult to hit. However, if you think to throw the all purpose bait into the water of the arena during the Snake phase its actually drawn to the bait to make it a MUCH. MUCH easier target. How to turn this one into a Best Boss Ever? Fire off arrows at random. A person with quick reflexes who just starts shooting... may get all three hits in under three seconds. And find it works every playthrough.
 * 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 learnt 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 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 requires dextrous swordplay at the same time. 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 - 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 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. 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.

Others Part 1
"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.

Others Part 2

 * 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.
 * 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 PlayStation 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.