Goddamned Boss

"I'm the biggest boss that you've seen thus far

Cause it's just another day in the life of a God damn boss"

- Rick Ross

First, let us say that he is not That One Boss.

These bosses are not particularly difficult or dangerous, but are an absolute pain in the butt to fight (one of the proposed titles for this trope was Pain In The Boss for this reason). Sure, your character may be able to last all day against this boss's attacks, but your patience certainly cannot. Frustration leading to mistakes is the most common way that players end up getting killed by these bosses.

In short, the Goddamned Boss is the boss equivalent of Goddamned Bats, while That One Boss is the boss equivalent of Demonic Spiders. Or phrased another way, he's actually fairly easy to beat once you've seen through the annoyance factor, deciphered his attack pattern and come up with an effective counter-strategy.

Common traits of the Goddamned Boss include:
 * Attacks that cause an Interface Screw
 * Attacks that throw you to the other end of the arena or even out of it.
 * A weak spot that's nigh impossible to hit
 * Employs numerous Standard Status Effects, especially ones such as Sleep or Confuse that impede your ability to control your character
 * Frequently runs or teleports out of attack range
 * Get Back Here Boss
 * Incredibly high Hit Points
 * Regenerates its incredibly high hit points
 * Taunts the player constantly
 * Uses Mana Burn, Mana Drain, or some other form of Power Nullifier
 * Is sandwiched between long cutscenes or a drought of Save Points. The boss may not be much of a danger, but if you fail then you have to wait for a while before you can try to beat it again.
 * Is a Flunky Boss, especially if the flunkies make it awkward to damage the boss itself without getting hit.
 * The battle mechanics are painfully repetitive.
 * Has That One Attack which heals the boss or makes it invincible for a while, making the length of the fight dependent on how the AI Roulette is feeling that day.
 * A Tactical Suicide Boss that has an attack that lets you hurt it, and rarely uses it, at random.
 * If it's an optional boss, it may qualify as one of those if it's a major pain in the ass to summon him at all.

Sometimes overlaps with the Marathon Boss.

For bosses that are really frickin' hard, see That One Boss.

Action Adventure

 * Moldorm from the Tower of Hera, the third dungeon in The Legend of Zelda a Link To T He Past: It was a gigantic worm, yay, whatever. It fought you on top of a platform with open edges and a hole in the middle. And the Knockback from hitting it in the wrong place would very, very likely send you plummeting down a floor (two floors if you fell down the hole in the middle). In which case you'd go back upstairs, pick up a heart or two, and realize.. the fight has started from the beginning. Any damage you did? Gone. It got faster the more damaged it got, making it more and more likely that it would knock you off and you'd lose more work.
 * The Moldorm is the first boss of The Legend of Zelda Links Awakening and has pretty much the same schtick. The seventh boss is an evil eagle who likes to blow you off the tower and will also instantly regenerate if you fall off.
 * The third form of Puppet Ganon in Wind Waker is basically Moldorm, except instead of the pits, it instead has a very specific weak point that you need to hit with a light arrow. Simple, right? Only, it moves around the ground very fast so that you'll have a hard time hitting it. It doesn't pose any threat to you, but it's still pretty damned annoying. There is a redeeming factor to this fight, however: the music.
 * Fraaz from The Legend of Zelda Spirit Tracks, especially in the final stretch. He switches between fire and ice attacks, and while charging up one, he is weak to the other, which can be exploited by using the boomerang to pick up the fire/ice left over from his previous attack and hit him with it. The thing is, this has to be done several times repeatedly in the last stretch, and if you're not quick enough or get hit with even one attack, you have to start the whole time-consuming process over again. To clarify, in order to complete the Take 'Em All On challenge and fight, he has to be fought two extra times.
 * That Twilit Bloat that is the last Tear of Light in Twilight Princess. First of all, it's electrified- imagine the unholy union of Barinade from The Legend of Zelda Ocarina of Time and a gigantic tick. He flies, naturally. You're on this floating wooden platform in the middle of Lake Hylia, that of course tilts with your weight, and that he can swim under and knock you off of. The only time you can attack him is after he tries to attack you (for a FULL HEART of damage- and you only have five at this point), assuming you managed to both dodge him and are still close enough to reach him. And if you've managed to do this three times, you have to leap on top of him and attack his little tick legs all at once.
 * Judge Doom, the Final Boss of Who Framed Roger Rabbit is easily hit and can't really hit you effectively, but his stamina is far beyond absurd. Worse, when he's been knocked down and you have a chance to finish him off with a can of Dip, Judge Doom inexplicably gains the ability to kill you with one hit!
 * The Mother Monster from Crusader of Centy just sits there without doing anything whatsoever. It is easy to kill if you know which of the (couple of dozen) weapons you're supposed to be using, but of course there's no hint as to what that might be. Use anything else, and you can just whack at her for half an hour without accomplishing much.
 * Misery, Doctor and Undead Core in Cave Story. Although battles aren't annoying, all of them are preceded by a set of dialogue which have to be read again and again, should any of these boss battles fail.
 * The dialogue goes much faster on each subsequent encounter.
 * Also, the game's True Final Boss . He's definitely hard, and interesting, but not hard enough to count as That One Boss (as in, not hard enough by True Final Boss standards). No, he's a Pain in The Boss because to get to him you have to go through the long Bonus Level of Hell, which is hard enough by itself, and fight ANOTHER challenging boss immediately before it without saving or using the full-heal boxes. To quote Yahtzee, it's like eating an entire bucket of corn on the cobb without getting a kernel stuck in your teeth.
 * In Shadow of the Colossus, several of the Colossi may fit this role, but the one that comes to mind first is Avion. To defeat her, you first have to get on top of her, which requires you to wait around until she gets near you and then execute a perfectly aimed and timed jump when it does. You lose your grip (and the ability to attack) whenever Avion makes a mid-air turn, which she spends most of the battle doing. If you fall (and you will), you have to swim all the way back across the huge lake-arena via a lazy breast stroke, which is frustratingly slow and takes an enormous amount of time.
 * Pelagia is also incredibly tedious to fight. The idea is to use the Pelagia's lip to jump up to the top of a small building so he will put his forefeet on the roof, exposing the weak point. Everything from getting his attention close enough to the building to jump to him, succeeding in jumping to his lip, succeeding in jumping to the building, and making the jump to his weak point is absolutely maddening.
 * Actually, there's a trick to it. Beating him the conventional way is infuriating. Beating him the speedrun way takes no time flat and there's no frustration involved. It's also rather fun. Does having a "trick" to him disqualify him from being a Goddamned Boss?
 * Basaran, if only because getting him to stand over a geyser - and have him centered over it so that it hits him - can be a pain to accomplish.
 * From La-Mulana, Baphomet could definitely qualify for a Goddamned Boss. While he doesn't have all that much health, and bombs (his primary weakness) do damage even if his wings are closed, the witches are what make this battle infuriating. There are about 4 witches on the screen at a time, and they vary from white (lightning bolts if you're in their field of vision), green (shoots fireball that goes through walls), light red (fast, shoot a large energy ball), and the most infuriating, gray. They're slow, but they fire a projectile that goes through walls and stuns you after the knockback (even in midair), which have a nasty tendency to hit you while you're trying to jump onto the main platform. Those gray witches will make you wish you were able to burn them. Also, he has a few attacks that are hard to dodge.
 * Bahamut is even more annoying. You fight him in a tiny-ass boat that drifts back and forth across the screen. You can't control it, only being able to influence its speed. Bahamut, meanwhile, will pop out of the water on the left and right sides and either charge you, breathe fire, or spit projectiles. If the boat drifts over him, you're going in the water, which hurts you even if you have the Scalesphere, and God help you if you get stuck under the boat.
 * If you can time the boat's oscillation going back and forth, you can goad Bahamut into doing attacks you can easily avoid. Of course, the trick is to actually doing it.
 * Tiamat, oh boy. Her room has four infinity symbols that can be destroyed, and it's highly recommended that you do. If you don't, she attacks with her hair in 8 fixed directions (and they're in an awkward offset) making it almost impossible to get close to her for a respectable amount of time to hit her. Not only that, she spawns Goddamn Bats which increase in number over time.
 * One particularly annoying boss is  from the second No More Heroes game. The fight consists entirely of the red one fighting you up front and the blue one standing on the catwalks above shooting at you. You're supposed to position yourself so the blue one's attacks hit the red one, but occasionally, the attack will outright go around the red one to make sure it hits you. Once you kill the red one, it then degrades to grave-camping, as you basically just wait for the blue one to come revive him, the only opportunity you'll have to hit him.
 * The other Shinobu boss, Million Gunman, is pretty frustrating as well. He's a Get Back Here Boss who will dodge roll out of any attempt to directly attack him, moves around a multi-tiered stage really fast at random, forcing the player to rely on Shinobu's jumping mechanics to even get close to. He's also somewhat of a Marathon Boss, as he takes a very small number of hits before taking off again, and can knock back the player with his fairly powerful projectile attack. And he doesn't shut the hell up.

Action Game

 * In God of War III, there is truly one that is not difficult to kill (On easy or normal mode...), but hard to fight. The Cerberus/Satyr fight in the underworld. The monster dog does a number of things to simply drive you insane. First, it spawns smaller dogs that explode, up to three at a time. Sure you can kick them back at the Cerberus if you are lucky. It has a three prong massive fire attack, while easy to avoid is unblockable, last but not least it uses it's claws to swipe away your health, this is easy to avoid. After you tear off one head is when things get interesting. Now a Satyr shows up to help. If you manage to kill it and tear off another dog head, TWO more of these things show up! So now you have serious problem. This boss is the Goddammed boss of the game when played on Titan mode or above. Apparently you are supposed to use Hermes' Boots to help with the battle according to Youtube, but locking on to the right enemy is far from easy, most of the time you'll end up locking on to one of the exploding dogs instead, very frustrating.

Beat Em Up

 * Streets of Rage 3, the end boss of Stage 4: the mysterious samurai ninja robot(?) named Yamato. He splits into three separate entities (oh which, chivalrously, only one will face you at a time), with four life bars each. His default behavior is to keep his distance and wait for the player to make a move (or throw flaming shuriken at a passive opponent). When you get too close, he'll either immediately make a flying leap to the other side of the arena or run you through with a lightning-fast sword dash. If you back him into a corner, he'll either Flash Step right behind you for another slash-dash or turn briefly invincible and run over anything between him and the opposing corner of the arena. He has some other tactics too, such as turning briefly invisible and throwing shuriken in triples or splitting into two unhittable mirror images that symmetrically dash through everything in the upper and lower edges of the area. However, with a lot of practice, finding weaknesses and goading him into doing just those things that leave openings for attack gets simple and he turns into a slightly more arduous Marathon Boss.
 * Carrion from Spider-Man and Venom: Maximum Carnage isn't particularly strong or durable, but is annoying due to his ability to levitate and turn intangible.

Fighting Game

 * Suika Ibuki's final spellcard in Touhou: Immaterial and Missing Power includes getting rid of more and more of the HUD as you damage her (getting rid of the health bars last).

First Person Shooter

 * In Metroid Prime 3, the second phase of the final battle takes a really long time, about twice the other two phases put together, but is substantially more mechanical and less fun. You're most likely to screw it up because you get impatient with how it's taking forever.
 * On a similar note, the last Dark Samus battle in Metroid Prime 2 is a giant exercise in frustration not because she's difficult, but because there's a seven minute time limit and the damage calculators are set so that she takes very little damage on the rare chances you have of hitting her. So for most of that seven minutes you're just helplessly staring at her cheap invincibility waiting for her to take her sweet time to give you a chance to hit her. Incidentally, this is only on hard mode. The damage calculators on normal mode are such that beating her is much less of a chore.
 * Despite being much easier, the first Dark Samus battle is a pain near the end. Dark Samus starts shielding near the end, making it impossible to hit her while she's using one of her attacks. However, when she's not attacking, she's zipping around the room so fast you can't keep a lock on her. So basically, the only way to do it is to just spray the room with Power Beam shots and hope they hit her. While she only has about a quarter of her health left when she does this, it's a pain because the fight just drags on and on.
 * The Grapple Guardian also has the potential to be a major pain in the ass, just because it's so hard to effectively stun him to get good hits.
 * Mogenar from Prime 3 takes almost an hour to beat on Hyper difficulty. His only weaknesses {orbs on his shoulders, stomach, and back) are shielded 75% of the time, and heal over time. Then if you do wind up destroying one, he stops and grabs another one to heal himself. The fight itself isn't that challenging, just long and stupidly annoying. It doesn't help that you only have the Power Beam in this fight and it's early in the game so you're low on health anyway. The kicker is, that to actually cause real damage to it, you have to jump into Hypermode once the orb is white, shoot it with the Hyper Beam (which saps your health), and use it really quickly so it doesn't go for the recovery orbs.
 * Speaking of Metroid Prime, the eponymous creature's 2nd form is this. It's completely immune to everything except the Phazon Beam, which can only be used if you stand in a pool of liquid phazon. Where are these pools? Prime excretes them occasionally. Prime's phazon excretion is completely random though, meaning you may end up jumping over shockwaves for way longer than is reasonable before you can finally hurt her. Oh, and each Phazon Beam shot only lowers her HP by 1/8.
 * The first form of Prime is just as annoying. It's only vulnerable to certain beam weapons at a time, which is fine. The problem is that in the last quarter of the fight, it changes its vulnerability very quickly, and some of your beam weapons are not fast-moving. By the time your Ice or Wave Beam has reached Prime to hit, it could've changed its vulnerability one or two times, making the shot ineffective. Combined with the Plasma Beam's relatively short range, the only weapon that can do consistent damage is the Power Beam, and even then, you'll be lucky if you can hit it more than a few times before it changes vulnerability again. Combined with the fact that in this phase it gains no new attacks, it just drags the fight out much longer than is reasonable.
 * The Gunship battles in Half-Life 2 are this if you don't understand how the rocket launcher works, which many players do not thanks to the only explanation being by Colonel Cubbage at a time when you might not even be anywhere near him.
 * To a lesser extent, Striders, but they don't move as much and don't shoot down your rockets.
 * The final boss of Opposing Force. The pattern is simple: shoot out his eyes with the cannons, fire into the portal in his stomach, kill the Shock Trooper he spawns, then repeat. There's barely any challenge; by this stage of the game, one Shock Trooper is barely a threat, the boss's attacks are telegraphed way in advance, and there's a health pool in the other room, safe from anything the boss can throw at you. However, the collision detection for the portal in his stomach is very fiddly, and there's no way to tell if you're actually doing anything until the boss dies, which usually takes a while.
 * The Energy Leech in Duke Nukem Forever. It's not enough that you probably don't have many suitable weapons for this fight, being stuck with the crappy rocket launcher. Nor is it enough that the big monster is fast, fast, fast. No, they had to put the fight underwater, meaning you have to struggle with swimming controls and watch your breath meter. Swimming into streams of bubbles, meanwhile, will put you in perfect range of his main attack.

Hack and Slash

 * Diablo II: Lord Of Destruction gives us its Final Boss, Baal. He teleports, burns mana, creates clones of himself, casts spells that can push you nearly a full screen back, and has a rather annoying laugh.
 * Also in Diablo II: Lord Of Destruction there's Nihlathak, the boss of the aptly named Nihlathak's Temple. He spawns minions and uses a devastating corpse explosion attack on downed minions.
 * And Diablo II itself gives you Izual. He doesn't hit that hard and you can life leech it back quickly, but has so freaking many HP that the recommended method to kill him as a melee class is to weigh down your attack key and go for a snack.
 * Also from Diablo II, there's Blood Raven, who constantly runs around at breakneck speed while summoning tons of zombies that get in your way.
 * Alpha Azieru in Dynasty Warriors Gundam 2. It's not Devil Gundam-level difficult, but if you're in the wrong place the goddamn funnels will hit you no matter where you try to move, sometimes three or four times in a row. It can shave off quite a bit of your health in the process.
 * The Undead Pirate Captain in Baldur's Gate: Dark Alliance 2 has many health points, can deliver average (but not excessive) damage and resurrects his undead henchmen, meaning that you'll have to deal with them again. The only advantaged character is Alessia the cleric, who can use Turn Undead to wipe them out and destroy their corpses.

MMORPGs

 * Monk bosses in Guild Wars have an unfortunate tendency to be able to heal themselves very quickly, making it difficult to do enough damage to kill them. And Dwayna help you if there's another monk enemy in the boss's spawn.
 * One of the worst is a mission where there is a Monk boss and a Mesmer boss (crowd control and interrupts) together. Neither does a large amount of damage, but one makes it hard attack properly while the other heals what attacks do get through.
 * In City of Heroes, Reichsman has 225,000 hit points. A team without regeneration and/or resistance debuffs is in for a loooong fight.
 * Actually he does not regenerate his health. However in the villain version of his task force he has a phase-shift power that makes him impossible to damage and he cycles in and out of phase. If you didn't bring a Mastermind class on your team (or lost the Mastermind player for any reason) you cannot get the temporary power that neutralizes this ability.
 * World of Warcraft has Mr. Smite, the Prophet Tharon'ja, King Ymiron, and other bosses who pause the action before changing their attack pattern. Very frustrating the first time around if you just blew your cooldowns, with better gear merely annoying to wait most of the fight on the pauses because the boss just loses HP that quickly. Ymiron has four pauses like that.
 * You can wipe on Heroic Pit of Saron on Garfrost because you did too much damage for him to throw the saronite you hide behind. In Lich King anyways.
 * Razorgore in Blackwing Lair has become this now that players are high enough level that he's no longer a threat. You have to force him to destroy the eggs before you can kill him, so while his HP is insignificant by Cataclysm standards, you have to sit through a fairly long and tedious process if you're not the controller, killing adds that require hardly any effort if you're past their level range.
 * Perfect World has Kun Kun, a boss who is a huge coward and so doesn't attack at all, only running away. He also has full spell immunity and absurdly high physical defense. He really isn't a problem for most classes (Melee classes and Archers just smack/shoot him to death, Venomancers sic their pets on him, Clerics use Plume Shot and their other physical attacks), but Wizards and Psychics have to run up and physically smack him with their wands/soulspheres for 3-4 damage per hit. Another complaint is that he tends to run straight into groups of aggressive mobs. This is obviously another problem for Wizards and Psychics, but also for melee classes because most of the mobs in Kun Kun's area are casters and heavy armor does not protect very well against magic, sacrificing magic defense for physical defense.
 * DC Universe Online has Harley Quinn, Complete with two different mallet attacks that will knock you across the room for massive damages, stun and ground attacks that cripple most ways of dodging her, even better she can't be harmed DURING the mallet attacks that are annoyingly long with annoyingly short periods between them to actually hit her! Once you figure out the cues to her attacks you can stay out of the way then rush in to hit her before running off again, but it's still a long fight. BONUS, she comes in two modes, normal and Challange once you hit Level Cap...have fun!
 * End-game bosses in Aion tend to have the Recovery ability, which is an uninterruptable attack that restores usually about 1/6th to 1/5th of their HP. Because they can use it without fail, and thanks to AI Roulette, they can use it back-to-back, a party that's capable of beating the boss normally will quickly find their patience running out when the boss heals almost back to full while they can do nothing about it, even if the boss is in the same situation (i.e. unable to kill the party). The accepted and understood method of killing these bosses is just to do damage fast enough that Recovery just drags the fight out, as opposed to making it unwinnable.

Platform Game

 * Duke Nukem Manhattan Project has the Bonus Boss Wozma. It's an immobile green sphere with about ten times the health of any other boss in the game and takes a good half-hour of repeatedly jumping up and firing off rockets at it before you finally do enough damage to kill it. What do you get for your trouble? An icon on your saved game. That's it.
 * Sonic the Hedgehog:
 * The boss of Carnival Night Act 2 in Sonic 3 & Knuckles is this unless you exploit Sonic's insta-shield move. Before you can attack you have to wait for him to circle after you, drop a big ball, charge up his tractor beam, outrun said beam, and then, finally, you can hit him once or twice while he retrieves the ball. Then the whole sequence repeats while your timer ticks ever closer to the deadly 10 minute mark since you're at the end of a very long level.
 * Sonic Rush Series's bosses are often like this, taking their sweet time doing nothing but you can't hit them, or giving you very little room to hit them without being stupid hard. Sonic Rush Adventure completely averts this--the bosses take millions of hits, but you can hit them often and they are usually quite short. Even the one that takes just four hits as you have to navigate an obstacle course. At least you're doing something.
 * The second Sonic vs. Shadow fight in Sonic Adventure 2 is ridiculously easy to not die on, but actually doing damage can be difficult, as Sonic/Shadow is almost always capable of making himself immune to your attacks (and has excellent reflexes).
 * It's also possible (if you time it correctly, or just get lucky) to
 * Speaking of SA2, Sonic's Egg Golem fight can sometimes become this thanks to a glitch that messes up sonic's jump.
 * Metropolis Zone in Sonic the Hedgehog 2. In a game where most bosses can be hit several times in a row (and some can be hit the required eight times before it's finished it's first attack), it takes an age to beat. It's surrounded by seven flying canisters, which rotate around the boss, meaning you can't just strike at will like most other bosses without risking damage. Doesn't help that it darts along the floor both ways, so you have to jump over it (a full jump as Sonic and Tails, hope and pray you're jump is timed so the balls are lower as Knuckles, or you will get hit). It then centres itself, expels the canisters round itself, before pulling them back in horizontally, which is when you attack. After a successful hit, it releases a canister, it opening to reveal a balloon Eggman. Bursting this gets it to start all over. Once you're rid of all the canisters, it tries to ire a laser at you, which is very quickly destroyed in comparison of all the waiting for an opening you would've just endured on the previous seven hits. This was made so much easier in Sonic & Knuckles, where a change in jump physics meant you could get all the hits in after the Metal Sonic had gone through that pattern once, unless you were dumb enough to grab the fire shield, which would mean you'd have to do it the long way.
 * Sonic's fight with Iblis in Sonic the Hedgehog (2006) just might be the king of this in Sonic games, if only because of how boring and drawn out it is. Unless you have the Purple Gem (which at this point in the story, you won't) you'll spend about a minute and a half between each attack just standing there waiting for Iblis to expose himself. God help you if you miss an opportunity to attack him.
 * Egg Emperor in Sonic Heroes is just plain obnoxious. He spends most of its time backing away from you just fast enough to be hard to hit, and it has HP in the hundreds, when the most damage you can do in one hit is around four. Of course, to do that much damage, you'll have to find "power cores" that are hidden in various parts of the arena, most of which are risky to try to get to for one reason or another. His attacks are easily dodged, but just disruptive enough to get in your way when you're trying to attack him. He isn't even particularly difficult--he just takes so long to beat that you're practically guaranteed to slip up eventually.
 * Time Eater from Sonic Generations. Not only is it the glitchiest part of the game, the other characters never shut up.
 * FromMega Man 1, Fire Man. It's not that he's terribly difficult to beat, but that it's nearly impossible to avoid getting hit a few times in the process, unlike the other Robot Masters. The reason for this is his inconsistent firing pattern which makes it very challenging to time jumps to avoid them, and in some cases makes it quite literally impossible to avoid. He also creates small flames near or even underneath where you're standing or jumping, which can force you to land in a spot where you won't be able to dodge an oncoming shot. Even with hitting him with his weakness, the player is likely to suffer a couple of hits - not so bad when he's the last boss of a stage, but can be absolutely infuriating during the end-game Boss Rush, the only one in the whole series that gives you NO health bonuses after defeating the bosses and forces you to start from the first boss all over if you die during any of them. Of course, if you know a rather cheap strategy of how to beat him, he'll be much easier.
 * Though this doesn't help much in Wily's Castle...if you just sit there and rapid fire shots at him, taking whatever hits come your way, you can essentially "damage race" him to victory. Not the SMARTEST strategy...but it does work. if by some off chance you're losing (he never leaves his place if you just KEEP shooting at him as he's programmed to "return fire" when he takes a hit...even if it doesn't register damage) you can still attempt to dodge, but you may end up missing out on valuable "damage him time" and take more damage without returning any. But again, though you wouldn't do this in the Wily stage Boss Rush, Fire Man is essentially a "stand there and shoot at each other as fast as we can" fight. THIS IS NOT TRUE AT ALL IN THE PSP REMAKE.
 * Actually, Fire Man's OTHER secret works well all the time. Just let him attack first. Jump the fire, and since the little flame lasts for a short time, you can dodge it. When you land, shoot him. It takes a bit of practice, but you can beat him very easily with this strategy. The only downside is that he can damage you after the fight, which can be dodged anyways.
 * Bright Man from Mega Man 4 also counts, as he has an ability to stop time and then body slam you while vulnerable. This is impossible to avoid and hurts a lot. Bright Man is the bane of anyone trying a no damage run.
 * Not entirely true. Bright Man's time-stopping ability can be stopped with ease if you know the secret. It doesn't make him any less annoying though, as he loves to abuse Collision Damage and is equipped with a Spread Shot cannon, which is another boss annoyance point in and of itself.
 * Kingfin in Super Mario Galaxy isn't difficult, he's just insanely annoying. After you get the first hit on him, he'll surround himself with several torpedo fish which have a nagging tendency to get in the way of your attacks against Kingfin, no matter how perfectly you've lined up your shot. The fight essentially just devolves into a pattern of find a shell, swim around a while looking for Kingfin, find him, line up your shot, watch it hit one of the torpedo fish instead of Kingfin, curse your bad luck, and then start the pattern all over again. This fight can take a while.
 * Also Bouldergeist in a standard playthrough (on the Daredevil run, he's an outright That One Boss). On this difficulty, the fight consists almost entirely of running around and grabbing rocks to hit him with. It's pretty easy, it just takes a little while.
 * The music that plays during these fights makes up for it, though.
 * The Koopa Clown Car in I Wanna Be the Guy. It has three forms. The first two are really easy, but involve sitting through around two minutes worth of animations every single time. And you'll be doing this a lot of times, because the third form really is hard.
 * If you die in the room right after the boss fight, you have to do the entire boss battle over again.
 * Hell, even if you do remember to go back the entrance to the previous room isn't level with the ground, so you'll try to go back and find that you apparently can't.
 * The battle with Mr. Patch in Banjo-Tooie, in which the player has to aim at randomly appearing weak spots while struggling with clunky flying controls.
 * It is possible to fight him from the ground. Of course, that glove thing doesn't help matters.
 * Trouble Bruin in the tower level of Dynamite Headdy. You climb a tower with little platforms on it, forced-scrolling up. He uses a tool to remove sections from it, so you have to keep moving up. Keeping pace is very easy. Sometimes he will decide to move in (the only way you can get hurt besides falling, which is not instant death in this game), and that's when you can hurt him. It's random whether he moves in or just keeps taking chunks out of the tower, and you can be there for quite a while. Most players good enough to get here could last all day, but it's still easy to get yourself killed out of impatience. The game even gives you a secret bonus point for taking a long time on this boss, as if to say "here's a consolation since the RNG is being so damn mean to you". This, combined with the game's split difficulty, hurts the game's Speed Run appeal significantly.
 * All four of the bosses in Sonic Spinball are Goddamned ones to an extent. While their arenas aren't particularly deadly and the bosses themselves can't kill you, all of them can knock you out of their arena and back to the level (though fortunately they don't heal when they do this), and they all take quite a few hits to kill, which can take forever without some practice. Oh, and most of them can summon flunkies.
 * King Croacus from Super Paper Mario is guarded most of the time by his armor, has spinning flower petal blades the size of Bowser cycling (albeit rather slowly) through the arena and is somewhat difficult to hit. He's not hard, he has relatively low HP, and is easier once you figure out that you can grab the giant spinning blades and throw them at him (which is a little unintuitive since that's the sort of thing you tend to avoid in games).
 * Mimi is relatively easy to defeat, the problem is that to beat her, you have to hit her with the jewels she throws at you, knocking her partially off the ceiling, and unfortunately, it's pretty easy to misjudge the jump to Goomba Stomp her, and end up crashing into her, hurting you instead.
 * Lord Vorselon in Ratchet & Clank: A Crack in Time. His attacks aren't particularly hard to avoid, but they are annoying (mostly being variants of Beam Spam), he loves to hear himself talk, he can be quite a Damage Sponge Boss depending on difficulty (made worse in the first fight with him by your limited weaponry), and he has this nasty habit of turning invisible, during which time he is invulnerable, but can still attack you. Oh, and sometimes he reappears off-camera. The fight with him can degenerate into "Vorselon appears, attacks you while you chip a small sliver off his health bar, then disappears" ad nauseum.

Real Time Strategy

 * Dawn of War II gives us the Avatar of Khaine, and the warboss, to an arguably lesser degree, both of them near-endgame bonus bosses with what feels like more HP than all other bosses in the game combined, a considerable repertoire of near instant kill attacks and 'spells,' as well as the ability to call in the most powerful units of their respective races as reinforcements. The only way to defeat these monstrosities tends to be a good twenty minutes of hit and run attacks with your ranged squads, and if you should lose focus only once, there is a good chance they will be swathed with a well placed area of effect spell, forcing you to repeat the entire process. Oh, and they do of course regenerate HP at a disturbing rate.
 * The second sequel Retribution gave us a more straight example in Mad Meks who you fight in the first Ork mission on the Space Hulk. He's armed with a Rokkit Launcher that will blow the crap out of vehicles but do pretty piss poor damaged against heavily armored heroes, doubtlessly not enough to ever overwhelm the healing you can do with liberal applications of the items/abilities you have at your disposal. However his armor has a chance to teleport anyone who melees a reasonable distance away from him. Thus the majority of the fight will be spent telling your own units to run up and hit him in the face over and over again without ever being in any real danger of losing. The fact that he can immobilize everyone temporarily or take damage to his energy bar rather than his health doesn't help either...
 * In the Protoss mini-campaign of Starcraft II, the player fights Maar, a protoss-zerg hybrid and an extremely annoying boss. Every time he is brought down to zero health, he returns to his spawn point and regenerates before coming back for another round. To make matters worse, Maar keeps doing this until the end of the mission, and comes back stronger ever single time. What stops him from being That One Boss is the fact that he's not all that tough; Because of his massive energy capacity, a single high templar can take out half his health with its disruption ability.

Roguelike

 * Smeagol in Angband. His attacks deals negligible damage, but he has a lot of health, moves quickly and can steal your money whenever he hits you. Even worse, he teleports whenever he steals from you and you could't get your money back until a recent update. Also, he's invisible (though warm-blooded, so you can see him with infravision if you're the right race and he's near) at a point when you usually can't yet See Invisible. At least he usually drops great items when killed (not anymore - over the last several versions the chance that he'll drop a pittance of copper pieces has been steadily rising).
 * Also, later bosses that can heal and teleport self. Can be close to impossible to kill if the "smart monsters" option is on - normally monster casting is a 1-in-X chance (it can be 1-in-2 or even 1-in-1), but in smart mode they are able to choose (with a high probability) which spell to cast (for example, healing about 10 rounds worth of your damage).

Role Playing Game
"BECOME MAGNUS AND BE FREE!"
 * Tortigar in Skies of Arcadia. He only has two attacks, a normal attack and a hit-all attack, neither of which are particularly damaging. However, he has rather high health, tends to spend every other turn making himself invincible, and has the ability to fully heal all of his health and WILL do so at least once every time you fight him. The main strategies for beating him are either spamming Spirit moves and hoping he isn't invincible/healing himself on that turn, or saving up your Spirit bar to its maximum, using one of your Limit Break techniques that make your enemy skip a turn, and hope he doesn't heal himself during the two or three turns you're recharging.
 * Bosses in Marvel Ultimate Alliance games aren't particularly hard in and of themselves. Unfortunately, these bosses do nothing but spam attacks that knock your heroes all around the room and interrupt your attacks. Plus, while they can knock you all over the place, they themselves are completely immune to Trip, Stun, Popup, and Grappling. This reaches head against wall levels when you find that a party full of Mighty Glaciers and Flying Bricks can be kicked around by minor villains whom they should realistically be able to one-shot. Basically, every boss fight slaps your entire team of superheroes with The Worf Effect. This was slightly improved in the second game, which gave larger characters like the Thing and the Hulk "knockback resistance," so they could no longer be Punched Across the Room.
 * Lavos' Outer Shell, in Chrono Trigger. It's a Boss Rush against... well, every boss in the game (skipping a handful of sub-bosses like the R-67s and Beast Keeper). But their stats have not changed in the slightest, so you'll be one-shotting a great deal of them, meaning about 90% of the battle is waiting for Lavos to announce its next form, killing it, and waiting for the game to catch up. (The other 10% are Black Tyranno and Giga Gaia, which are still kind of tricky.) Fortunately, if you choose to slam the Epoch into it, you skip this part.
 * Made finger-eatingly infuriating if one happens to take the wrong party to fight Lavos' Boss Rush form, because Lavos imitates Nizbel: a boss who has unreasonably high defense unless hit with a lightning attack. When you fight the real Nizbel you're forced to have a character in the party who uses lightning, but against Lavos you can walk into the fight lightningless and still be fighting it an hour later.
 * Before each fight, you're shown what Lavos will mimic next, along with a chance to change your party and heal before you attack it. So even if you don't have Crono, Magus, or Robo with you at the moment, you won't be forced to fight a Marathon Boss.
 * ...which just makes it doubly annoying if you didn't realise there was a chance to change your party.
 * Some of his forms will Mana Drain you upon death. You have a breather to drink some Ethers (and probably have quite a few to drink), so it's not really dangerous so much as the giant space bug giving you a big ole middle finger for no real reason other than sheer spite.
 * Chrono Cross gives us a Goddamned Boss Rush: the elemental robot-things in Terra Tower. They have quite a few hit points (and tend to spam healing elements at the worst times). They also love to spam status buffs and debuffs to turn the entire field to their elemental color, which sends the power of their elements through the roof. Combine this with Cross' already severe Ending Fatigue and you have a recipe for maximum annoyance.
 * The also counts, if you're going for a proper ending. You have to use a specific combination of elements on it, but its AI will cast elements to screw up the combination. If you run out of elements, you'll just have to run away and try again, which gets tiresome quickly.
 * Not really, since this is easily averted if you realize that you can simply keep a big stash of differently-colored elements at level one, as the level of the element makes no difference whatsoever when creating the sequence. Even the  itself, while innately a level 8 element, can simply be equipped as a level 1 element with no difference in effect at all (which would be moot by that point because the   would be permanently stunned after casting the final element anyway, but still is worth noting). Also, so long as you simply get max stamina on every character before casting anything, you will always have enough turns to cast all seven elements in order, regardless of anything else. If you do nothing but cast level 1 elements in the proper order until you run out of stamina and then be forced to recover, the boss will simply pass its own turn and give you another turn to finish, permanently stunning it and allowing you to use the   to instantly destroy it and free   for the good ending.
 * Many of the bosses in Star Wars: The Force Unleashed can be these if you're having an off day. They end with mandatory Action Command challenges, and if you keep screwing them up, you'll wish you could just give 'em a basic slash and call it a day. Same deal with Spider Man: Web of Shadows.
 * Oh dear god, Symbiote Wolverine.
 * Jr. Troopa in the N64 Paper Mario.
 * To elaborate, he has higher defense than most enemies to begin with, and gains a new immunity with each battle. And this being a game where you only have three or four modes of attack, that's a big deal. Your only options are to spam certain partners' attacks - and the more effective ones tend to cost a ton of Flower Points - or to come into the fights (which are all totally unannounced) specially equipped.
 * Fights against him (and in fact, all battles in the game) become way easier if you keep the Spike Shield badge on the entire game. You won't ever have to worry about jumping on things (unless they're on fire) for the rest of the game.
 * Also from the N64 Paper Mario, Big Lantern Ghost. You fight it in a dark room, where you can't target any enemy unless you can see it; the only enemy you can see is its lantern, which you must hit at least twice so that you can attack the Ghost in the first place. Except that it blows out the lantern on a regular basis, forcing you to keep. doing. this. Making matters worse is that one of its attacks hits your partner (which forces you to miss their turn for multiple turns at a time) and is nigh-impossible to guard against with your Action Commands except by pure dumb luck. And speaking of Action Commands and pure dumb luck, the battle routinely lags if you're playing the Virtual Console release of the game, making even basic timed hits obnoxiously difficult and the battle much harder than it needs to be.
 * The bosses in the Mario & Luigi series for Gameboy Advance and Nintendo DS are juuust beatable with normal attacks to qualify as this, instead of Puzzle Bosses. Most bosses had high HP, a weak point, regenerative abilities, and even flunkies. Sometimes a boss fight done wrong could take an hour, literally. Remember the rock monster slash tree thing outside the Toad village in Superstar Saga? Yeah, like that.
 * Partners in Time's final boss marathon. The final boss alone has two phases, obscene health, heals every few turns, has a weak point that can only be attacked after destroying two other weak points, and they regenerate too, it attacks multiple times per turn and deals high damage. A true evening-filling final boss.
 * The boss of the official Morrowind plug in Siege at Firemoth (Grum) has 2000 hp with a regeneration effect while the final boss of the first expansion pack (a Physical God) has 3000 HP and the second's (an aspect of a god) has 2000 HP at most and both have no regen. If you have decent resist shock effects he can't hurt you, but he takes forever to kill.
 * Shadow Mitsuo of Persona 4 takes forever to kill, constantly giving himself a 1400 HP buffer that is pretty much impossible to stop. Beyond his AI randomly getting lucky and using both of his actions to attack the hero (instant game over if he dies) he poses no threat but is a war of attrition.
 * Rogue Galaxy has this boss battle around chapter 6: first you must get into a mine and fight a drilling-mining-robot-thing, which is painstakingly slow to defeat since you have to finish off each arm first. After that, he just keeps running around and hitting you with a drill that comes straight out of his...well, you get it. After a very LONG battle, you find out that it was not the end and you still have to fight the guy controlling it. With the newest member of your party alone (whom, of course you're barely accustomed to play). To make it even worse, said enemy can kill you in a few shots and moves way faster than you can, and the only real way to kill him is to keep blocking until he reloads, making the battle take a long time even when you know what you're supposed to do. Since blocking isn't that useful for most of the game, there are high chances you will lose; fortunately, there's the possibility to save your game before but, guess what? There is NO SAVING POINT between the previous battle and this one so if you happen to lose (which is most probable) you'll have to deal with the drilling-ass robot again. Alluring, isn't it?
 * In Kingdom Hearts Re: Chain of Memories, the final boss of Reverse/Rebirth mode, Ansem, is like this. The entire fight basically consists of using card break duels, and he has maximum HP. Very tedious.
 * The final boss of the main story mode in Chain of Memories also counts, thanks to having a set pattern of very easily-avoided attacks, and giving you plenty of time to heal if you do get hit, but only being vulnerable at one small time window during that pattern (and having the maximum amount of health possible in the game).
 * Ruler of the Sky from 358/2 Days isn't particularly difficult. It's pattern is pretty basic, and it's attacks don't hit that hard. However it has a LOT of life and the entire battle is spent in the air where it will outrun you. This all adds up to a VERY long boss battle.
 * Zip Slasher in particular is like this, but because of the inferior AI and battle system, lots of the enemies in this game qualify. Devastating attacks, but just falls to the same pattern spammed over and over again, but you have to keep doing it and if you mess up, you do it all over again.
 * Ursula's first form is probably the first game's standout example. She constantly guards, is aided by her eels (who constantly declare "No escape!"), and can only be attacked by overflowing her cauldron with magic--but the game never explains exactly how that works.
 * One of the Bonus Boss in Wild Arms 3 is Arioch, The Duke of Vengeance. True to the name, he's very easy to beat when you encounter him the first time, but afterward, he will, emphasis on will, stalk you. Meaning that every random encounter will have a chance of you encountering Arioch. The mechanics is that Arioch starts as a level 1 boss. His level goes up every time an encounter happens. So, assuming the player's level is constant and is around lvl 70 when he/she triggers Arioch, about first 30-40 encounters will be cakewalk, the rest to 70th medium, and in the last 10 encounters: painful.
 * Beldr in Devil Survivor, particularly on a New Game Plus. Even if you have level 99 demons armed with Megidolaon and Deathbound, you, the main character, still have to, which means the battle still takes many turns and you're railroaded into building your Strength stat for the first 3 days. Damn you Norse Mythology!
 * Actually, Strength stat doesn't affect the damage does to Beldr, it's mainly level-based damage... doesn't mean you won't have to do some Level Grinding just to beat him, however, since the Hero's character level ALWAYS resets on a New Game Plus.
 * Shot Mothers in Phantasy Star Zero. They appear randomly every 10 floors in a bonus dungeon with 101 floors, and you cant leave to tower for more items. She isn't strong by any means, but her annoying attack pattern of gliding across the room coupled with the lack of items makes her a very annoying fight.
 * Jade Empire gives you Death's Hand. Despite being implied to be the Big Bad for a good half of the game, the fight against him consists almost entirely of hammering him with repeated blows, then dodging his massive but cripplingly slow attacks. He was immune to stun and most status effects, so all you could really do was wait for his HP (or your sanity) to run out.
 * The Final Boss of Final Fantasy VIII, Ultimecia. Granted, this is suppose to be the last battle you EVER fight, but consider the setup for all this frustration. It starts as a straight fight, you VS the sorceress. After that, however, she summons a Giant Space Flea From Nowhere that was apparently  to give you the beating of a lifetime. After you kill the creature, Ultimecia decides to merge with that Guardian Force (although they should both be too weak for combat at this point for having their asses handed to them) to create a hybrid creature. Finally, having defeated THAT, Ultimecia is back AGAIN, because getting thrashed and exploding wasn't enough, so now there's a faceless sorceress with even more power than ever for no apparent reason. This may be the last part of the last boss, but consider what you had to go through to get here and how long you had to go through the same battle cycles because the boss has WAY too many hit points and forms. Couple this against the game's system where you can't get a level advantage on any boss EVER and presto! GODDAMNED BOSS!
 * Of course, if by that point you haven't figured out how to A) abuse the junction system and B) abuse the limit break system, it's very difficult. If you HAVE figured out how to abuse the previous two systems, all you have to do is make sure Squall can do Renzokuken every turn, and the last boss will quite literally die long before the battle is over (the final form has to say specific lines, regardless of HP, and so will continue to exist and be pummeled well after it reaches zero HP).
 * This same game also has Jumbo Cactuar and the Tonberry King. The first one is a veritable damage sponge that takes an hour to bring into low HP, and after that, it fucking escapes if you do not give him a very powerful finishing blow. If the bastard escapes, you have to start over. The Tonberry King by himself isn't very annoying, but you have to fight twenty normal Tonberries to initiate a fight with him. Tonberries are powerful and high-HP enemies, so twenty battles with them are pretty much guaranteed to be repetitively unleashing your most powerful G Fs and Limit Breaks on them. Sitting and watching the animation. MANY.TIMES.OVER.
 * The third Weigraf fight in Final Fantasy Tactics is often viewed as That One Boss. At least until you learn the secret to beating him, at which point the fight becomes absurdly trivial. The fight is a one on one fight between Ramza and Weigraf, and the trick is to obtain the self-healing reaction ability (Which isn't that hard, and is a pretty strong ability anyway, so the player may already have it), and then spam Ramzas stat boosting abilities so that you can instantly crush Weigraf, and the even nastier Velius battle that follows. However, this can take a long time, as you spend time running away from Weigraf while constantly using your stat boosting abilities. The Weigraf / Velius fight thus ends up being That One Boss or a Goddamned Boss, depending on how you tackle it.
 * The Thresher Maw in Mass Effect 2. It only has one attack- firing blasts of acid at you, and there are no other enemies to fight, but the battle can be very frustrating because A) it has a ton of health, B) the Thresher can destroy some of the cover around you and frequently shifts position on the battlefield forcing you to constantly be on the move, C) it uses its acid blast attack frequently and said attack rips through your shields like a knife through butter, and D) you're on a 5 minute time limit the whole fight. However, despite the fact that running out of time doesn't cause you to lose, if you don't beat the Thresher by then you won't get the best reward, not to mention that destroying it is an in-universe and out-of-universe Crowning Moment of Awesome.
 * It is somewhat less difficult if you have enough ammo to use heavy weapons like the Collector Particle Beam or the Cain on it. However, even when using these you have to be careful about your shots since it moves around the map so often.
 * Cornix Canor in The World Ends With You. A Get Back Here Flunky Boss who picks up battlefield obstacles, screwing with your psychokinesis (and sometimes your shockwave, depending on the angle). Its flunkies are seemingly only there to give Neku something to do, while blocking Shiki's attempts to actually hit the boss itself. It's rather fitting that this boss is the one chosen to, in-universe, waste Neku's time.
 * Every boss from the Golden Sun games with some kind of Djinn screw either counts as That One Boss or this.
 * Hargon used Healall! Hargon's wounds fully heal! Hargon used Healall! Hargon's wounds fully heal! Hargon used Healall! Hargon's wounds fully heal! Hargon used Healall! Hargon's wounds fully heal!
 * After Dragon Quest II, most bosses (especially Final Bosses) no longer have any healing spells, and if they do, it's the considerably less effect Heal or HealMore, instead of HealAll.
 * Mara is this in Shin Megami Tensei III Nocturne. He'll use Diarahan EVERY SINGLE TURN unless you can kill him before he uses it. That means you have to drain his 2300 HP in one turn. Hope you have Bright Might!
 * What a dick.
 * in Shin Megami Tensei Strange Journey. If you can't deal damage fast enough between his rounds of healing roughly 1,000 HP, you might as well reset and either rearrange your demons or go grinding.
 * Hari-Hara from Digital Devil Saga isn't too bad in the first form, but the second form is made ridiculous by the numerous floating cores that accompany it. Each core absorbs its respective element (making group attacks out of the question), and gets a turn of its own and will deal a single target, high level attack - so pray to Vishnu it doesn't hit a certain member's weakness. Thankfully, all but one of the cores are weak to the opposing element, but if you defeat a core Hari-Hara will regenerate it or another fallen one the next turn. Oh and Hari-Hara itself likes to dish out random status ailments with Vanity, making it harder if you thought you could get lucky with Cielo in your team.
 * The boss on the DLC of Lost Odyssey, Killalon, is incredibly irritating. For starters you have to run down 25 floors of dungeon before you can fight him, with no save points. Although he doesn't have that much HP, the fact that he regens it a lot makes him hard to kill, and as you near-constantly have to protect your characters from his moves any damage you do will likely be recovered. Even with 5 level 99 characters and the best skills in the game, defeating this boss is somewhat reliant on what moves he actually decides to cast.
 * Touhou Project Pocket EVO+ "story fights" generally consist of one of your characters against a single opposing character. Sometimes this is otherwise a perfectly normal fight. Sometimes the opposing character has a Defense-increasing or healing spell card and will not stop spamming it ...
 * Erika from Pokémon Red and Blue can qualify as this, with two of her three Pokemon knowing the Wrap/Bind moves (which, back in the day, did continuous but light damage over the course of 2 to 5 turns) and two of them using the status-inflicting Poisonpowder and Sleep Powder. Wrap/Bind was obnoxious because it prevented switching and forces the player's Pokemon to stay in for however many turns it lasted for, all just to do a pittance of damage. And while Poison and Sleep are easily cured with Antidotes and Awakenings, it forced the player to waste a turn dealing with the status. This could make Erika very annoying if the player's Pokemon were unable to take hers out in one shot.
 * Annoying? Try deadly. Thanks to the broken game balance in Gen 1, Wrap prevents your Mons from doing anything. If you're slower than them, you're fucked.
 * There's also several opponents in Colloseum/XD whose only strategy consists of spamming Double Team, essentially turning beting them into a Luck Based Mission.
 * Pretty much every boss in Endless Frontier. Each and every one of them (And there are a crapton) has lots of team-hitting attacks, Forced Evasion, Some really tough flunkies and enough HP to eclipse Bill Gate's total income four times over. Granted, So do normal enemies, but not to the ferocity bosses do. Expect to spend a solid half-hour fighting a boss.
 * The afterling under the Celestial Tree in Baten Kaitos Origins. You have to cut its roots before Valara can kill it. This is easier said than done. For one thing, the afterling inexplicably attacks Sagi's party, as opposed to the person who's trying to kill it. Also, it'll occasionally shift its posture so that your party can't hit it without killing it; with the way the game's targeting system works, however, it's possible for the thing to shift just as you attack, resulting in you unleashing an EX Combo against it and killing it. Finally, when you do cut it loose? Valara kills it in the following cutscene. This fight doesn't compare to the pain the Holoholobird put you through, but it's frustrating and the solution is counterintuitive.
 * The Hearteater you fight in the Matar Highlands. It has quite a bit of HP and hits fairly hard, but the real problem is its special, Ovulate. This infests a character with the thing's eggs, and puts a timer on them. When the timer runs out, the eggs hatch and devour the party member (read: One Hit Kill). Basically, you can either burn up your MP using the Chalice of Freedom, or you can just revive whenever someone goes down (pretty much constantly).
 * Wiseman, once you get past the Nightmare Fuel. His regular attacks drain both your health and your MP. Meanwhile, one of his specials, Cast Away Your Carnal Robes, knocks your whole party down, removes any magnus you've equipped, and breaks your combos. As a result, you're gonna spend most of the fight trying to keep his HP down and struggling to assemble a decent combo, while he uses your stolen MP to hit you with special after special. Adding to the pain, he comes right after the Black Dragon, which is a much tougher fight. Thankfully, most of his attacks are fairly weak; his strongest attack, Illusory Chaos, does maybe half your health in damage, which is easy to recover from.


 * From Dark Souls we got Lost Izalith's boss: The Bed of Chaos. You don't get to fight it directly, instead you got to rush through the arena in order to destroy 3 weak points that go down in one hit. However, as the fight progresses, the floor will crumble and the boss will start spamming hard-hitting and night-unavoidable attacks that can easily knock you down into the freshly opened Bottomless Pits. Fortunately, every time you destroy a weak point, it stays destroyed even if you die or warp back to a bonfire, which is actually a more viable strategy than trying to destroy the 3 targets in one go.
 * Both of the truly optional bosses in Wasteland - the Scorpitron and the Nightmare. Since the Scorpitron is available for you to fight pretty much from the beginning of the game, he doubles as That One Boss for most players because he's a big challenge even for a party that just finished the game (but didn't spend much time on leveling up). The Nightmare, however, resides in an optional dungeon, and you don't have to fight him to complete it. He isn't particularly dangerous, he just has the highest HP in the entire game and you can only have one party member enter the dungeon to begin with, which makes his fight long and tedious (if not for macros and the fast-forward button). This can also lead to Can't Catch Up, since he also gives the highest XP in the game for killing him (and double that if the final blow is done via melee) which can easily earn your solo character a level or three.

Simulation Game

 * Naval Ops: Commander has the Archaeopteryx, which is a big airplane. It is extremely fast, VERY hard to even hit and follows a "hit-and-run" tactic.

Survival Horror

 * Rule of Rose has the Mermaid boss, which isn't necessarily difficult, but the fight can get so drawn-out and monotonous that you mess up out of frustration. Come to think of it, boss fights in general aren't the game's strongest suit....

Third Person Shooter

 * Gears of War 3 has the Lambent Zerker. She's actually a pretty climactic battle in campaign, where she shows up only once at the end of a frantic defense of fortress at Anvil Gate. Her appearance in Horde Mode is another matter entirely. She has the opportunity to show up every tenth wave, and is one option of five that can be selected at random (the others being a regular Berserker or two, a squad of Reavers, four or five Gunkers, or a lone Brumak). The Lambent Zerker is easily the worst of the lot because of her staying power--she is vulnerable only when she opens her chest plate (which, if the mood strikes her, may be once every 60 seconds or more), and even then is a Damage Sponge of mythic proportions. She also has the tendency to charge willy-nilly around the map, casually smashing the fortifications you've spent the past nine waves saving up for. The worst part is that Gunkers and Brumaks are tougher enemies, while a regular Berzerker is a more strategic fight--the Lambent Zerker isn't very hard, just annoyingly durable.

Turn Based Tactics

 * The Incubuses in the tactical strategy Odium. They are pretty weak and their attack cannot really harm you (they launch exploding spheres which explode after a few turns, so if you keep your men away from them nobody will ever get hurt.) But their animations are horribly slow (and they attack twice per turn), and they happen to have a movement rate just a lil' bit faster than all of your men, which means that most of the fight will consist of you chasing them down and trying to get them into range of your weapons so that you can just barely scratch them while waiting through the horribly slow enemy turns. (Oh, and each sphere explodes individually at the beginning of the enemy turn, further bogging it down.)
 * Super Robot Wars Original Generation has the R-Gun Rivale. Comes near the end of the level when your characters are all fatigued out, regenerates energy and life, has a force field, and has an attack with very high range. You may use a strategy that sucks up all his energy and hence can not use his ultimate attack (for a time, at least, since he regenerates energy), but he has a backup in the form of Gundam's funnel-like weapons. He has 50 uses/durability for it, though. Do not play on an empty stomach.

Wide Open Sandbox

 * Half of the boss battle against Gary in Bully involves chasing him on a scaffolding whilst he dumps wheelbarrows full of bricks on you from above. whilst bragging about how awesome he is and how much Jimmy sucks. the second half involves punching him whilst he makes NO effort to hurt you.
 * Which makes perfect sense. Gary's a Manipulative Bastard who hid behind others for the entire game. Of course he wouldn't stand a chance in a fistfight against the scrap-happy Jimmy.