SNK Boss



""Hey, who allowed them to join this tournament? They're way too strong to compete; I mean, what's up with that? Someone is going to have to take that team down!""

- Announcer, Capcom vs. SNK 2

""Hey, don't take this as an excuse or something, but... that Ragna at the very end? That sucker is TOUGH! Oh my God, you have no idea!""

- Hazama/Terumi, Blaz Blue

An SNK Boss is a boss in a Fighting Game who breaks the rules that enforce Competitive Balance to an absurd degree that they are insanely overpowered when compared to any character in the player's arsenal. The SNK Boss combines Nintendo Hard with The Computer Is a Cheating Bastard, and takes them Up to Eleven. These types of bosses usually contain the following factors.


 * 1) Lack of Certain Functions and Limitations. While you may have to switch between high and low blocking, the SNK Boss needs to only block one way. Where you have to crouch to perform certain moves, the boss does not. Where your super meter is, the boss has no visible one or his restores itself faster than yours, and can use as many as it wants.
 * 2) Blatantly Overpowered Attacks that do not leave the boss vulnerable to any punishment if missed or blocked. A trademark of the SNK Boss. Where you have fireballs, the boss has full-screen lasers that deal a ton of damage, cannot be stuffed out, and come out lightning fast. If you have an invincible uppercut, the boss likely has one where he surrounds himself with lightning for more hits and damage, and can cancel out fireballs. These types of bosses sometimes, but not always, have a maximum level super where they show off their superiority by utterly annihilating you regardless of your current health, usually combined with Finger Poke of Doom for maximum insult.
 * 3) Overpowered defense: they may be the gameplay equivalent of The Juggernaut, being able to continue their attack startup against your own hits or possess features like a larger health bar, reduced block-stun, inability to get dizzied (or a shorter dizzy period), or they can interrupt your combos with an attacks or escape from a juggle via some sort of recovery/teleport.

If the boss is playable, such as upon defeat, they are significantly weaker and more balanced for actual play. A non-weakened playable SNK Boss is most certainly banned in any competitive tournaments where it would be a Game Breaker for one human player to use on another.

In some fighting games, the Final Boss is a unique opponent in both design and ability (such as a 30-foot Eldritch Abomination) that is Purposefully Overpowered and only appears in single-player/non-competitive game modes; it's slightly more sensible that such a boss would have those high-powered attacks rather than a human-sized villain. It can also feel pretty good for a player who manages to use an otherwise-mortal Badass to beat the crap out of a godlike monster.

These bosses originate from the days of arcade machines, where the high difficulty level was used to separate players from their pocket change while attempting to register their initials in the top spot of the machine's High Scores table. In console games, side effects of continued exposure to an SNK Boss may include broken controllers and increased sales of GameSharks to "cheat back". Occasionally, these bosses may have an Achilles Heel that utilizes special moves from characters that usually have limited utility. It is unknown whether these are intentional or not.

Takes its name from the company SNK, which seems to love making bosses like this and having each successive one top the last. This is also a case of Follow the Leader, especially with Arc System Works.

Subtrope of Fake Difficulty and The Computer Is a Cheating Bastard. See also Perfect Play AI, whose difficulty arises less from outright cheating, and more from a flawless battle strategy.

See also Boss Dissonance. Don't be surprised if they can only be toppled via Fake Skill.

Trope Namer: SNK Playmore

 * (Video Montage of SNK Bosses, you may want to refer to this video on occasion.)
 * This being SNK, the King of Fighters series had loads and loads of these:
 * The SNK boss by which all others are defined is Rugal Bernstein from The King of Fighters '94. His first form is cake, but once round 2 starts and that tux comes off, pray:

He uses a variation of Geese Howard's Reppuken and Wolfgang Krauser's Kaiser Wave that go through all other projectiles and have priority over everything. Also, he has his own move called Genocide Cutter which he uses with reckless abandon. It can shave off 40 to 70 percent of your lifebar, depending on whether the computer wants it to be so. He's easily-hit with most Jump Kicks, but they do so little damage that even this go-to attack won't win easily.
 * The series upped the ante considerably in '95 with Saisyu Kusanagi followed by Omega Rugal:

Saisyu loves to fireball spam and uppercut. A lot. He's harder than Omega Rugal, and that's saying something.

Omega Rugal is...the same Rugal from '94, but with white hair, no shirt, dark skin (Or pale and zombie like in 2002), a large Omega symbol branded into his back, hence the name, and A SUPER MOVE!
 * '96 had two bosses in a row with Chizuru and Goenitz and there's also a Boss Team.

Goenitz is difficult to hit, let alone beat. If the computer felt like it, Goenitz could be completely unbeatable by any means. He has a wind barrier, the Yonokaze, which can come out directly in front of your character, can't be rolled through and blocks all projectiles. It could also appear anywhere between you and Goenitz, meaning that rushing towards him or approaching him just increases the chance of you strucking yourself against this invincible pillar of wind. The only thing capable of breaking it was Leona's rushing slash kick.

Also, if somehow Yonokaze spawns exactly in front of Goenitz, you will get winded up. Oh, and if the AI goes into a loop and does it repeatedly (its downtime isn't NEARLY enough to give you an opening to attack), then nothing you can do will have any effect whatsoever.
 * '97 had Orochi Iori (or Leona), the Orochi Team, and then Orochi himself, all in a row.

Orochi has Mu Ni Kaerou (Return to Nothingness), a screen-filler attack: it basically turns him into an open Ark of the Covenant. Block it, and you will take unusually high damage for a blocked attack. Don't block it, and you're gone. However, unlike the other bosses on the list, Orochi's AI was poor. Had it been at the level of the previous bosses, combined with vicious priority attacks, Orochi would have been near unbeatable.
 * Then came '98, which had Omega Rugal once again.

This time, he has a whole slew of new moves, such as the fusion of Kaiser Wave and Reppuken called the Gravity Smash (with nasty priority, and covering his body when he charged it, making it hard to hit him out of it) he swaps out God Press in favour of Vanishing Rush (which is what it sounds like, complete with being fast enough that you barely have a moment to react to it) his Destruction Omega super move (a grab that does ridiculous amounts of damage), a devastating super called the Rugal Execution (which drains your health at a very rapid rate) and an update of the Genocide Cutter, the Dark Genocide, which is a 3-hit version of the original.
 * The Updated Rerelease of '98, Ultimate Match, has Orochi, Goenitz, AND Omega Rugal as bosses. Which one you encounter depends on how many super finishes you get on your opponents. All 3 of them have increased stamina.

The boss who was changed the most was Goenitz, who is even CHEAPER than in 96. Not only can his Winds of Night hit you while you're knocked down now, but he has a new command attack, a new special move, and vastly upgraded super attacks.

Orochi has been revamped from his original incarnation and now has a crouching animation, along with updated normals and several of his original moves switched around, but his Mu Ni Kaerou screen filler super still does ridiculous damage, and if you're positioned exactly in the middle of the screen and don't block, it does double the amount of hits and damage. 50% plus 50% equals 100%. Yes, it instantly kills you if you're in the wrong place at the wrong time.

Omega Rugal is roughly the same as before, except slightly faster.
 * Krizalid was the boss in '99.

He had a pansy first form like Rugal, with a 2-hit projectile that would win over your projectiles. In round 2, he burns off the coat, and starts spamming a Tornado Kick attack, the Typhoon Rage, which has priority over everything, and Lethal Impact, which looks like an axe kick, but can hit high, overhead OR low as a command throw, OR counterthrow! In short, projectiles and throws are the only things that one move could not counter... and he sometimes spammed it if you closed in on him. His supers, at max level, do 90 percent of your health bar!
 * Clone Zero in '00 had a screen-filling super that did 60+ percent damage and could easily Guard Break your characters with his Cutter Arts, which did multiple hits whether it was the special or super version.
 * Original Zero in '01 is the same as his clone, except for the fact that he already has 3 strikers to make up for the lack of moves that Clone Zero had: Ron, (a "Guard Breaking Striker") Krizalid, and a huge black lion named Glaugan, mainly to differentiate him from his clone. Again, he suffers from the same Achilles Heel as Krizalid and Clone Zero.
 * And, finally, we come to Igniz.

Fireballs with absolute priority, cheap whip attacks which have ridiculously long range and could lead to infinites which he will use if he ever feels like it, can cancel ALL of his moves (except DMs) into EVERYTHING (including a DM) and has a super called Brutal God Project where he rushes you, pins you in the corner, whips you, hits you with the edges of his cape, does one of his own supers within this super, and finally engulfs you in a ball of energy, the whole combo doing roughly 80 PERCENT DAMAGE!!!.

He also earns one point for Overkill: most multi-hit attacks are interrupted when the target is knocked out (or they continue, but the victim falls) but for Igniz, if you are with only 1 HP and are struck with his Brutal God Project... you will take the whole attack until he allows you to give your KO scream. It's possible to defeat him, but you have to play his own game for that. Whatever the case, Lord have mercy if you attempt to beat him at Level 8 difficulty.
 * To conclude the NESTS saga, we have 2002, which has, by far, the cheapest version of Rugal to date: One Hit Kill Combos by the dozen, the return of Reppuken, 3 Kaiser Wave variants (the last of which is unblockable and the first of which comes out faster than the speed of light), a 3-hit Genocide Cutter...

To make up for it, his MAX2 is a series of Kaiser Waves which are horribly inaccurate. Unfortunately, it STILL does a sickening amount of damage. And in the unlikely event you Dodge Roll in front of Rugal when he's charging a Kaiser Wave, it'll STILL hit you while he's charging!

And if that wasn't enough, there's a Game Breaking Bug with the Kaiser Wave. [http://www.youtube.com/watch?v=5fxoulcPogc&feature=channel_page If he happens to release it at just the right moment that you come out of the Dodge Roll, it hovers. FOREVER.] So basically he would have this one ball of energy floating behind his ass (or in front of his crotch, if you managed to switch sides) until he launches another Kaiser Wave (HSDM included), or grabs you (supers included, but check out what happens when you do his Gigantic Pressure) It's like Benimaru's hovering lightning ball HSDM, but evil, never ending and guarateed OHKO.
 * The remake of 2002, Unlimited Match, has all of the NESTS Saga bosses: Krizalid, Clone Zero, Original Zero, Igniz, AND Rugal! As per usual, all the bosses do decreased damage when playing as them.

Krizalid is, surprisingly, the most broken out of them all: he builds his super meter extremely fast, has horrid infinites, insane juggles and his MAX2 (Lightning Disaster, a full-screen attack that sends a bunch of lasers into the air) can hit you while you're on the ground and he can even juggle into it.

Clone Zero is roughly the most balanced out of all of them. To put that into context, he has no 0-stock infinites outside of Max Mode, while the other NESTS bosses do. His new MAX2 (Anryuuten Hazaki, a Shun Goku Satsu-esque attack) does decent damage as do all his other moves.

Original Zero is decently balanced, but can be considered cheap because he's much faster than in 2001, AND with some effort, can spam his Krizalid striker to juggle you forever. His MAX2, Kyou Hoshi Mikaijin, is essentially Clone Zero's, but with the addition of assistance from his Strikers, starting with Ron whacking your soul from your body and culminating with all three strikers ganging up to beat the tar out of said soul.

Igniz is exactly the same as he was in 2001. Unfortunately, this means he still has his Sagittarius Blade (QCF+ HP) infinite. His new MAX2 (Disintegrational Universe) is undoubtedly the most visually impressive - he traps you in a curse seal, which encases you inside a black orb that Igniz turns into a galaxy/nebula, and Igniz makes said galaxy/nebula explode. This particular move is no exception from the cheap rule. It can hit you while you're knocked down AND after Brutal God Project. And the damage doesn't get dampened.

And if you did not lose more than 2 teammates after beating the final stage (which consists of one of the first 4 aforementioned bosses), you enter a special battle against Rugal. He's roughly the same as before, and that means he has increased stamina for his boss version, his Beads Destructor now bounces you off the wall, his Kaiser Phoenix is more accurate and hits you while you're on the ground, (though as a trade off, its damage output is pathetic) and his AI is also much smarter: it doesn't spam Kaiser Wave as much, but remember that one glitch from the video above this entry? Yeah, it's still there. Oh, and if you lose the match it's Game Over.
 * The King of Fighters 2002: Unlimited Match brought Nightmare Geese, and gave him all sorts of enhancements to his moveset that made him the pinnacle of overpowered:

Lightning fast Reppukens, Shippukens that had no recovery time and could be fired TWICE IN A ROW, a Double Shippuken which much like its Fatal Fury: Real Bout Special version can be used twice, thus FOUR SHIPPUKENS, worse still considering it lacks the slight delay the RBS version had meaning a bombardment of them from a Griefer is likely, a Jaeiken that led into a juggle, the "Claw" Raging Storm that can now OTG, and many other edits that make this version of Geese one of the cheapest SNK bosses out there.

He also has a new MAX2 where he takes off his shirt and starts building a huge Reppuken, which he promptly blasts you with after it's reached roughly quadruple size (The activation's reminiscent of his lesser known Raising Dead End super from Fatal Fury Wild Ambition).

Couple all of that with the literally psychic AI that predicts every input you do and naturally responds with the correct counter for your offense and you have one of the most unbeatable bosses in SNK's history. Not only that, but you have to BEAT HIM in the last Expert Challenge in Challenge Mode to unlock everything. Good luck.

Oh, and to even unlock the challenge to fight Nightmare Geese? You have to pass a challenge that puts you up against ALL the NESTS bosses AND Omega Rugal, all in a row, survival-style. And Nightmare Geese is STILL harder. Thankfully, SNK decided to have at least a small amount of mercy for people who want to unlock everything but don't have super powers at fighting games: If you fail enough challenges, the game will still gradually unlock things for you.
 * Neowave was only released in Japan and Europe, and is essentially a tech demo for the Atomiswave hardware. There're no post-match quotes or endings and everything is pretty much recycled from KOF 2002... except from the unique-to-this-game version of Young Geese:

Priority over everything and with more tricks than a clown's pocket; he's capable of finishing you off even if you have 3/4 of your health. To make matters worse, the CPU version's Deadly Rave super is completely unblockable. Makes the Art of Fighting 2 version look like Karnov.
 * In 2003, if you manage to fulfill the condition to the true ending, you'll get to fight Chizuru and Maki Kagura as the penultimate boss. While Chizuru uses Doppleganger Attack, Maki spams it. You'll start the fight against Chizuru, but if she ever switches to Maki, good luck.

The game also marked the debut of Rugal's son Adel to the fray. Adel not only inherited his father's moves and essence of Badass (Sans villainy, he's more of an honorable chap), but also his SNK Boss Syndrome.

He lacks his father's Kaiser Wave until XI, but his Reppukyaku comes out very fast, his God Press is unblockable (including the Gigantic Pressure), and the Genocide Cutter is now a super which does a ridiculous amount of damage.

Mukai, the True Final Boss from the same game, surprisingly subverts this trope, as other than a full screen LDM that turns you to stone for a free hit, he has nothing that gives him power over everyone else.
 * Magaki from XI seems to be SNK's way of saying "we gave up trying to think of ways to mess with you, so here's a boss that throws more projectiles than a bleeding Touhou character... '''while you have no grazing option'".

He loves abusing his fireballs, to the point where there will be lots of them flying everywhere including ones that disappear halfway and reappear behind you. Then there are also the large, semi-invisible ones that move in an arc towards you. Said fireballs also happen to be 100% invincible, moving nonstop and crushing all projectiles, even super ones.

Then his psychedelic pink full screen-filler attack that will hurt your eyes the first few times (you'll get used to it). It's hard as hell to even get close to him, and if you do, he'll probably just throw you right back with his little frontal explosion whenever he feels like it.
 * XII had no proper boss character, despite rumors, but XIII gives us two: Saiki and Dark Ash.

Saiki is the leader of Those From The Past. Before the fight begins, he changes into a naked red demon with a blacked out face. He is an amazing block whore (except against some projectiles) and counters any and everything thrown at him by abusing projectiles that freeze you solid, stabbing you in the chest, freezing time, and pummeling you. He also has a super version of this move that sucks you in if you're too close and instantly stuns you. And of course, he wouldn't be a proper SNK boss without a screen filling attack, which just so happens to be his Neo MAX. A Neo MAX that disregards the rules and lets him do it with only 1 meter. He's also got some moves involving dark flames, too, which is a grab in ranged form. And just after you beat him, and you think it can't get any worse...

Then you fight Evil Ash, the True Final Boss. The fight takes place in a completely white void and Ash is completely covered in black flames. If you think this is only a powered-up Ash, you're wrong. This is Ash fused with Saiki with the projectile spam of Goenitz, the AI of Rugal, and a screen filling super that would make Orochi himself proud. SNK pretty much lost their minds when it came down to the difficulty of Dark Ash.

He has regular Ash and Saiki's movesets combined, but their rage-inducing properties are worse than you can imagine from the explanation alone. Unlike Saiki, who at least lets up on the fireballs, Evil Ash's fireballs have no recovery, and according to a movelist found out by hacking him in the PC leak of the Arcade version, they do not require charging either. That's right, all the CPU inputs is Back, Forward+Punch at super fast speeds. His AI is also psychic and he counters everything you do with a Flash Kick. Then he walks away and goes right back to spamming. By far the most infuriating part about him is that he has not one, but TWO Neo MA Xes. One of them is Saiki's screen-filler attack with no delay, and the other is Ash's normal command grab Neo MAX...followed up by Germinal. You heard right - he adds on damage to an already damaging Neo MAX, AND disables your specials in the process.

There are some weaknesses, though: said screen filler doesn't do too much damage to guard and, in spite of his supers, he cannot Max Cancel like a normal player... which is a blessing. Also, for some reason, neither Dark Ash nor Saiki seem to properly counter Mr. Karate's Shoran Kyaku rushing command grab - even at the hardest level, they always fall for it and take the damage to the face, which makes them disarmingly easy to beat for anyone maining Mr. Karate, especially since Shoran Kyaku can be spammed due to Mr. Karate always landing exactly within range to do it again immediately. The same is true for Vice's Splash command grab, which is slightly less accurate and more unsafe... but neither boss punishes a miss unless they feel like it, which is (thankfully) very rarely. Have fun!
 * SNK bosses crept their way into the Maximum Impact games, as well, with Duke and Jivatma.

Duke had an unlimited Super Meter and a nigh-unblockable super move that instantly breaks your guard meter if you're lucky enough to block it. As playable characters, both lose their special tricks with their super meters, but retain their Super Moves. (Though these require full bars to use)

Jivatma had an insane reach and a super move that damages you for 1/2 of your life bar (and he loves to use it just as you come down from a jump, so that you can't block). Oddly enough, he's actually easier to beat, because his super bar isn't at maximum all the time. (It just regenerates.)

Regulation A, the update of Maximum Impact 2, has Duke, Jivatma, and Nightmare Geese as the final opponents. They subvert this trope entirely, having no extra traits whatsoever.
 * The King of Fighters R2, for the Neo Geo Pocket Color, has Rugal as its final SNK Boss. His moveset and AI are almost the same as in 98.
 * Speaking of portable KOF games, we mustn't forget The King of Fighters EX2: Howling Blood, whose end boss is a Brainwashed and Crazy kid named Shinobu Amou, who was part of an experiment by Gustav Munchausen to transplant Goenitz's soul for reincarnation.

His AI isn't that hard... until Round 2 when he suddenly Turns Gold, becomes faster and more powerful, and starts hurling attacks from every single direction with absolute priority. Oh, and he changes elements from wind to lightning. You will HATE Shinobu, guaranteed. His winquote puts it perfectly into perspective: ""HAHAHAHAHAHAHAHAHAHA! I BROKE YOU!!!""


 * It should be noted that for several KOF games, if the player opts to use a continue, the player can choose from several power boosts, including reducing your enemy to 1/3 of his health. The maddening side effect of choosing this option is that your enemy recovers a little bit of health after every win. Combine this with the chance you may not be able to inflict more than a few pixels of damage on these bosses, and voila: Your enemy starts each round with more health than the previous round.

Also, bear in mind that most SNK bosses (Starting from Geese Howard in Fatal Fury) are, in some degree, susceptible to trips, throws or certain fancy attacks. (Leona and Goenitz, Lucky Glauber and Rugal, to name a few)
 * Don't be fooled by how cute and lighthearted SNK Gals Fighters, a.k.a. "The Queen Of Fighters", looks, this is one of the toughest KOF games to date. Aside from the final boss Miss X, there are two sub-bosses that need mentioning: Whip and Yuki.

Whip has most of her moves from The King of Fighters '99, but also has a move that lets her swing up and stomp you to the ground. She'll even go as far as shooting you while you're down.

Yuki, Kyo's girlfriend, looks harmless, and has no knowledge of martial arts whatsoever. But she's insanely fast and even uses a Big No for both offense and defense. One of her desperation attacks delivers 33 hits, the highest in the game. And another desperation has her eating a hamburger- that replenishes her health! It seems that she went the Yuri way and took several levels in badass.
 * Johann, in Rage of the Dragons, has fireballs that throw him backwards out of the way of almost anything coming over them. He also has absolute priority, takes no block damage, does ridiculous amounts of damage, and a prescient AI. Johann can also throw you (with appropriately Massive Damage) out of anything. Including a roll, a Super Move, and even another throw.
 * The Fatal Fury games predates all of SNK's previous games with Geese Howard.
 * In the first game, he was armed with a projectile that could cut off a third of your health, has incredible priority, and a counter-throw he could use against any attack he chose (even when you were simply jumping at him he could grab you out of the air with said counter-throw), setting the boundaries to be later broken by Rugal. Fortunately for the player, he suffered from the same bug as all other players: he's vulnerable for the first frame of standing up.
 * In Real Bout Special, Geese returns as the game's True Final Boss only if you have a high enough score after beating Krauser. This incarnation, commonly known as Nightmare Geese to fans (And later officially christened that), really IS a nightmare (Figuratively and literally, since the battle is hinted to be one big nightmare).

Not only do his Reppukens have absolute priority, but he can fire 2 Shippukens and 2 Double Shippukens (that's 4 Shippukens!) in the air! He's so broken that most of his Combos do 100% damage! This version introduced the claw version of his Raising/Raging Storm, which did a ridiculous amount of block damage, and he also has a newly super-powered version of his Thunder Break super from Real Bout ... which is now unblockable while jumping and hits at random places across the arena, even hitting the extra lanes! Worse still, lose to him once and it's Game Over.
 * Geese's half-brother, Wolfgang Krauser, shares some SNK Boss Syndrome, but only in his debut game: Fatal Fury 2. His AI is infuriating as all hell, and his moves hit incredibly hard. Oh, and the restriction about being at low health to use your super doesn't apply to him, meaning that he can Kaiser Wave you at any time.
 * Garou: Mark of the Wolves inverts this, with the sub-boss being the SNK Boss and the Final Boss being somewhat balanced.

The sub-boss, Grant, has several powerful attacks at his disposal which can decimate your health bar in mere seconds. Be especially wary if his T.O.P meter kicks in, because his moves will do extra damage, and you may end up getting killed by last-minute damage scaling.

The final boss, Kain, is surprisingly easy...until Round 2 where he gets a full T.O.P meter for the rest of the match.
 * The boss of the Play Station version of Real Bout Special, White, is a parody of Alex from A Clockwork Orange, but instead of just being a mere sociopath he's a CRAZY motherfucker who can brainwash people with his rod.

To start off, he doesn't crouch, backdash, run, or even jump, meaning you will never be able to predict what he's going to do next. Also, he has poison skull projectiles that go through everything (even Nightmare Geese's Reppukens!) and instantly dizzy you. His normal moves also cause a massive amount of hitstun, leading to infinites. Hell, even his poison skulls can lead to infinites. And if you deplete his health to the point where he can use his P-Power attack, better not jump because his P-Power move is a huge force field that takes off 3/4 of your life. He also has an S-Power super that slows you down.

Oh, and if you do manage to beat him for good, he uses a secret P-Power move where he fires an unblockable explosive laser at you from his rod that instantly kills you unless you jump over it. If he wins with this attack, he has a special winpose where he falls to the floor again, laughing like a hyena. He tries to control himself, but can't, and just continues laughing at you while rolling on the ground like a little kid. White, you ASSHOLE!
 * In Art of Fighting Mr. Big and Mr. Karate were hard enough. Geese Howard in Art of Fighting 2 made things worse.

Mr. Karate is extremely susceptible to jump kicks, and can be beaten pretty easily by just repeatedly doing these off the wall. The problem is getting to him in the first place - even at the lowest difficulty, Mr. Big is ridiculously hard.

Mr. Big can be easily crushed by jump kicks as well, just keep hitting uptoward and kick at the same time, you will jump kick him to death easily. In contrast, Mr. Big in Art of Fighting 2 is a complete joke.
 * And then came SNK vs. Capcom SVC Chaos. If SNK Bosses in general are considered to be The Syndrome, then this game is to be considered The SNK Boss Epidemic. Starring, but not limited to: Serious Mr. Karate, Shin Akuma, Athena and Red Arremer.
 * Zero, Goenitz and Geese Howard are SNK Sub Bosses. Run into the first one, you'll be shredded like a maverick. Run into the second one and you'll be spinning round like a record. Run into the third one and prepare to be cheesed to death by his Deadly Rave.
 * The SNK side final boss is a powered-up version of Mr. Karate, called "Serious Mr. Karate", which furthered his shenanigans.

His health and damage are higher than pretty much all other characters, his moves have insane priority and most are invincible on startup, and pretty much all of them knock you back across the screen, nullifying all that hard work you had to do to even get close to him.

Oh, and you know those huge fireballs (the Haoh-Sho-Koh-ken) the Kyokugen practitioners characters are fond of throwing? Yeah, he can do three of those. In a row. Normal Mr. Karate at least had it as an Exceed. Serious Mr. Karate has it as a NORMAL SPECIAL. THAT HE CAN DO AT ANY TIME WITHOUT LOSING A POWER STOCK.

Also, his Ko'oh Ken functions much like his 2002 counterpart (He is Takuma after all)...but now they have huge range and come out very fast. And they nullify whatever comes across them. Most of his moves do take off quite a bit of guard meter and he can easily guard crush you although you can't do the same when you get to play as him in the console version.

To finish, his supers count as special moves and his Exceed is completely unblockable, yet it has pretty poor priority.
 * The Capcom side final boss is Shin Akuma, who's just as cheap.

In this game, his supers that he used to have normally are considered special moves and take 0 super stocks to perform, with the exception of the Raging Demon (which is his regular form's Exceed). Worse still is that he has all the perks that Shin Akuma normally has (a full-screen Raging Demon and double air fireballs, insanely fast teleport with no recovery time).

But the worst part is definitely his Exceed, the Misogi, which homes in on your character's position, comes out lightning fast, and is UNBLOCKABLE. You have to be really lucky or skilled to avoid/counter that move.
 * Depending on how you did throughout the entire game prior to fighting either of the above, if you managed to beat Serious Mr. Karate, you go to Heaven to fight Athena. She's not the Athena you all know and love from Psycho Soldier and The King of Fighters. No, this is goddess Athena from Athena, and she lives up to that old game's Nintendo Hard difficulty.

All of her attacks count as supers but are actually special moves, much like Shin Akuma & Serious Mr. Karate. What makes her worse than both of them combined? All of them have absolute priority and do RIDICULOUS damage for special moves. Her Exceed is blockable, yes, but if she's already got you down to almost half of your first lifebar (which she will, guaranteed) and you don't block, it's an INSTANT KILL.

To add insult to injury, when she wins she turns you into an animal.
 * If you, instead, had to beat Shin Akuma, you go to hell to fight the Red Arremer. At first it seems like he's balanced, but then he starts summoning strikers that paralyze you. Then he starts flying. Then he rams into you. Then he chews on you and then throws you. Then you die. Then you get turned into a lowly demon.
 * The absolute worst part of both Athena and Red Arremer is that if you lose, you won't be able to try again and have to start over completely, much like Final Bison in Street Fighter Alpha 3. However, it's somewhat logical here, seeing as your character would never be able to fight again as an animal or small demon.
 * The Samurai Shodown series had many of these as well:
 * Amakusa in part 1 likes to bitchslap you into a corner and keep you there for an easy infinite. He also has 2 fireballs (one being unblockable), and he teleports like crazy and throws you as soon as he gets out of it. If you beat him in Round 1, a cutscene occurs where he powers up and unleashes the powers of his dark god to make him stronger and also harder.
 * Then came Mizuki in part 2, who had several moves that caused Interface Screw, or transformed you into a vulnerable PIG, in addition to using several of Amakusa's previous tactics.
 * Zankuro in part 3 could literally kill you in 3 hits. And you need to win 3 rounds to defeat him while he only needs to win 2 to defeat you. Bust Zankuro's Super Move unleashed a screen-height wave that WILL KILL YOU IF IT HIS YOU WHILE YOU ARE IN THE AIR.
 * Part 4 has you fight not one, nor two, but three bosses in sequence. The first is a CPU-only version of Amakusa with purple skin who is always in Bust mode (except if you also use a character who's in Bust Mode when fighting him). This version of Amakusa, sometimes called Aku-Amakusa, is NOT the SNK boss of the game, however, as he's the same as the player version. Upon beating him, you fight the real SNK boss, Zankuro, for the 2nd time in the series. He's more intelligent this time around, and his Heavy Slash cuts off half of your health bar. Afterwards, it's a cakewalk when you fight your rival in one final battle.
 * Samurai Shodown 64: Yuga uses levitation, has own slashes and unblockable grabs teleporting directly on opponent from any distance, has access to time stop, healing, teleportation, and few annoying projectiles. Before Yuga, you fight Deku, the catch is that Deku-Yuga team needs to win 2 rounds to defeat you, while you have to win a total of 3 rounds to defeat them (Sound familiar? You should however, have to defeat Deku once to face Yuga). If you are defeated by Yuga and continue, you are going back to fighting Deku.
 * Samurai Shodown 64 2 (Asura Zanmaden): In this game, Yuga's first form again has levitation, teleporting slashes, projectiles, ability to snag opponent's soul out of his body, and energy shield. Her second form has ability to turn her arms into weapons and stretch them via entire screen, has access to all kinds of projectiles, beams and fire waves, ability to slow opponent's movement, and her super involves dropping an energy sphere which results in nuke-comparable unblockable explosion, shockwave from which covers almost entire screen for major damage.
 * Warriors Rage (PS): Main boss Oboro has no body you can attack, since you fight his giant levitating weapons instead. Those weapons are the only "character" in game which takes full advantage of 3D space flying here and there and attacking from various directions - while their own hitboxes (which you should attack to damage Oboro) are almost nonexistent.
 * Samurai Shodown 5 and its mid boss Sankuro carry on the proud tradition of SNK Boss cheapness: First off his takes way less damage from attacks, plus his special attacks involve calling in annoying helpers (the sliding girl isn't so bad, but the guy coming down from the sky does a sick amount of damage, and the grabbing guy from behind is usually coupled with a healing move that restores almost a quarter of Sankuro's life bar). Add to it that his super is apparently an instant kill. Add to it the fact that Sankuro is only the MID-BOSS... yeah, Samurai Shodown has a bunch of SNK bosses.

Once you damage the final boss Gaoh enough, he goes to an invincible demon armor mode and will charge at you constantly like a rhino, and you have to wait until the mode ends.

And then, rounding out the previous two examples is Yumeji, Gaoh's Dragon. He/she is essentially Bust Mode Ukyo on steroids. He/she has a nodachi that can take off 3/4ths of his/her opponent's health bar in a single strike and an inescapable multi-hitting trap move that is almost as damaging, but much harder to avoid. And if that's not enough... he/she has the ability to transform into the other fighters and use their signature moves.
 * 5 Special has you fight Amakusa, Zankuro, Gaoh, and Mizuki in sequence, but the only ones who really qualify as SNK Bosses are Zankuro and Mizuki because Amakusa's AI was rather retarded and Gaoh was heavily nerfed. Zankuro is even more intelligent than in 4, despite being balanced somewhat, and he has a new counter move that he uses all the time. Mizuki lost her Interface Screw moves, but got a whole lot of new non-screwy moves that still make her a cheap bitch.
 * And in 6? Demon Gaoh, who's a bit of a Giant Space Flea From Nowhere, is the unplayable final boss you fight AFTER beating one of the above. He has several of Gaoh's more annoying moves, a fire explosion sweep that's really hard to get around, can bounce you off a wall and combo from it, has a Super move that all-out destroys your weapon and is invulnerable, a rediculously fast charging super meter, and will not drop/break his own weapon no matter what you hit him with.
 * Samurai Shodown Sen has sub-boss Drago, whose weapon is a rifle. This game goes for a slightly more realistic level of swordplay than the rest of the series (no wind fireballs here) so this is significant. His fighting style basically consists of backflipping out of your range, then raining destruction upon you for a crazy amount of time before he finally has to stop and reload.

Subverted by Golba, the final boss, who fights with a generic rapier attacks and seemingly lacks special moves.
 * What, you didn't think SNK would skimp on boss difficulty for their big Mascot Fighter, did you? All four bosses of Neo Geo Battle Coliseum (Neo-Dio, Mizuchi, (a clone of Orochi) King Leo and Goodman) have regenerating health, annoying attacks, and do an insane amount of damage.

King Leo abuses Nightmare, a counter where he went black and any move that hit was countered with a small combo, like a motherfuck. As playable, he loses his flaming kick special and King Upper.

Mizuchi is basically Orochi with an added touch of Goenitz, meaning that he will abuse an energy pillar special which, while Orochi possessed it before, did not abuse it as much. As playable, he loses his ability to create 5-6 energy pillars at once.

Neo-Dio teleports a lot and is an incredible block-whore. As playable, he loses his feather projectile and another move that held you in place.

Goodman is basically Igniz mixed with Magaki from The King of Fighters XI, and uses a whip to control a weird flaming monkey spirit. He can control it for as long as he wants, in any direction. And his super move actually makes it stronger. You will hate Goodman. As playable, he remains the same, but cannot jump or crouch and you can't partner him up with anybody.

Plus, due to the way the game's arcade mode is set up, you only get one shot at them before you have to continue.
 * Speaking of King Lion and King Leo, in their games, King Leo served as the final boss, basically possessing faster, stronger versions of Lion's specials; his stage, unlike all the others, had only one platform of sorts so you couldn't exactly jaunt all over the place to avoid his attacks. Furthermore, he gains a super that King Lion does not: the aforementioned King Upper which is sure to knock you into a worse situation than before. Couple that with a faster weapon throw (Both normal and the God Breath variant) and King Leo is a VERY fearsome bastard. Take him lightly? How silly you are!
 * King Leo was downgraded to sub-boss for Kizuna Encounter but STILL possessed all the deadly power he had in Savage Reign. the only difference being he swapped King Lion's God Breath for a stronger, faster variant called Thunder.

His place as final boss is taken by Jyazu. While he at first appears to merely be a Gozu/Mezu headswap that uses their moveset, they're faster than normal, he has a deadly whirling dervish-like atttack with his blades that sort of resembles Sonic the Hedgehog, he has a very Hundred Crack Fist-style SPECIAL attack, meaning he can abuse it and it takes off a lot of health and hits a lot, and a kick variant of said special, and his Desperation Attack summons an array of large fire pillars. And just to serve as a warning of how deadly he is, he appears to easily slay King Leo while still in bird form! Using the latter's own sword, no less!

Capcom

 * As expected, the Street Fighter series has many of these:
 * The original Street Fighter had Sagat as the final boss, who was not only the most powerful iteration of Sagat in the series, but also capable of knocking off more than half your life bar in one hit. And to top it all, all the now-standard Fighting Game special moves like Hadoukens and such were considered secrets at the time, with very few knowing of their existence, let alone the exact command to do them. And even then, Sagat could stuff fireballs and hurricane kicks cold. No tick damage, no knockback.
 * The original Street Fighter II had all four Devas as potential SNK Bosses.

Balrog / M. Bison (Boxer) loves his Dash Punch. A lot. So much so that if you beat him once he gets pissed in Round 2 and does a barrage of instantly charged Dash Punches and Uppers. 26 times in a row. Afterward he waits and does other normals...for all of about 3 seconds. Then he resumes. Your only option here is to low block and die. Not or die. AND die. Because the frames of his Dash Punch never give you an opportunity to strike. If you have less than 25% life, you are FUCKED. End of discussion.

Vega / Balrog (Claw) likes to jump on the cage in his stage all the damn time. A special mechanic was even built in to his stage so if you played as him on that stage, you could do it too. In Super, however, the move is no longer available to the player, but the CPU can still do this.

Sagat returns from Street Fighter, with some new moves under his belt. Not that it matters because all he does is spam Tiger Shots all day. And if you jump at him he will do a psychic Tiger Uppercut. The AI in Champion Edition, strangely, never uses the Tiger Knee. Hyper Fighting fixed this, so now he will occasionally do a Tiger Knee up close...then tick throw you for the win.

M. Bison / Vega (Dictator) is this type of boss in the sense that there is absolutely no way you can predict what he will do. His AI pattern is completely randomized and will surprise you at every turn with a high-priority attack via command-reading. Thinking of doing a fireball? Head Stomp. Shoryuken? He'll Scissor Kick you right out of it. Hurricane Kick? Psycho Crusher. Akuma/Gouki from Super Street Fighter II Turbo was this type of boss in his first appearance; he could teleport, was fast, did massive amounts of damage and could shoot two fireballs in mid-air. Furthermore, the secret playable version of Akuma/Gouki was less powerful than the boss version, though still so broken that he's always been banned from Tournament Play.
 * Apparently someone at Capcom decided that Akuma wasn't powerful enough, and thus Shin Akuma from the Street Fighter Alpha series was born. He regains the double air fireballs from Super Turbo, deals double damage with all of his moves, his teleports are completely invincible, and his Raging Demon now goes all the way across the screen.
 * Street Fighter Alpha 3 had M. Bison, whose Psycho Crusher attack is quite different between normal and boss versions in that it was huge and if not blocked did incomprehensibly high damage, and his teleport has 0 lag. The only way to hit him is to counter all of his attacks, which requires mind-boggling amounts of skill. Also, you can't continue if you lose to him.
 * Gill from Street Fighter III is incredibly hard to beat in one sitting. Projectile attacks that are much stronger than any of the main characters, a pair of special attacks that ate up screen real estate (and most characters' life bars, even when blocking), and the ability to fully revive himself after being knocked down make him a particularly controller throw-worthy boss.

On top of that, while you only have access to one of your Super Arts at a time, Gill can use all three of his. Just about the only upside is that during Resurrection, Gill is wide open, and a single hit stops the attack (although he also has a force field, so getting to him isn't easy) - so it's pretty likely he won't get back all his health. In addition, Resurrection shuts off Gill's Super Meter, so it can only happen once a round, for what it's worth.

It should also be said that if you happen to knock Gill out of Seraphic Wing or Meteor Strike (the former is more likely), he will keep his entire super bar. Thus, if he doesn't whip out another super (which has a very slim chance of happening), defeating him will initiate his usage of Resurrection. Luckily, if you continue a set amount of times in 3rd Strike the CPU's difficulty will be bumped down a level, which eases a bit of the pain of fighting Gill. You can tell whether or not the difficulty will be lowered if Gill starts using his taunt (read: "laughing his ass off at you"), which is something he never does regularly.
 * Street Fighter IV gives us Seth, Gouken and Akuma.

Seth is the half naked man-cyborg Final Boss. He seems like a pushover during Round 1, but then in round 2 he suddenly starts using his special moves that he copied off of the other characters. He also starts spamming teleports around like crazy and with such accuracy that you'll usually end up facing the wrong way and eating a Spinning Piledriver. Still, there are ways to get around Seth's omniscient AI.

If you fulfill certain conditions after beating Seth (provided you actually get to fulfill them), a slash will suddenly appear through the victory screen and a silhouette appears. If you, you fight Akuma. If you do that while also, you fight Gouken. Both of them are cake compared to Seth, though.
 * Super SFIV takes it up a notch.

Seth starts using special attacks he copied off the other characters as early as Round 1. If you survive that, Round 2 unlocks his super and ultra moves. And he can pull off ultra moves twice in a row straight, with no recovery time. It's practically a Luck Based Mission. However, if he has Ultra 2 he will always use it as soon as he gets up, no matter where you are. Be thankful Capcom did that. And when you finally get to play as him, he takes twice the normal amount of damage! Yes, his defense is the lowest in the game.

And if you fulfill the conditions necessary to fight Akuma after beating Seth, you fight Shin Akuma, who is Akuma in his 7th color palette (purple gi, darker red hair, reddish skin, basically Alpha Shin Akuma). Yes, He's Back, and more infuriating than before. He has 1000 HP and stun (same as Ryu), has his double air fireballs (normally an EX move) as a normal move, has an invincible teleport, and not only does his regular Raging Demon go faster and double the range it normally goes, but the Ultra version goes even faster, and across the entire screen. His Ultra 2 also hits on the very first frame, making it near impossible to dodge at close range.

Likewise, fulfilling Gouken's conditions gives you Shin Gouken, which is Gouken wearing his 7th color palette, making him look like the way Sheng Long was depicted (all grey gi). Many of his Specials now have armor break properties, and his Hadokens (including Ultra 2) are already charged to the max level. If you get hit by his Hadoken in a corner, blocked or not you WILL be trapped in the corner as he spams more Hadokens, safely chipping lots of life from you or outright taking away half your life in Hadoken combos if God forbid he tagged you unblocked. His Sengokugoshoha (the dashing palm attack) is also MUCH faster and has more invincibility. He may not be the worst boss ever, but you can't sleep on him as previously implied.
 * Arcade Edition ups the secret boss count to 4. But first the bosses proper:

Seth uses ALL of his moves, including Ultras and Supers, in round 1, and in round 2 he does combos which professional players already know, such as jumping MP into Toe Taps into Dive Kick for a reset.

Fulfilling the conditions for Shin Akuma and Gouken while  will give you Shin Evil Ryu and Shin Oni, respectively. Shin Evil Ryu can have more than 1 Hadoken on the screen at the same time, has a more invulnerable and longer teleport, and from that teleport he can cancel it into any move he wants, including his Raging Demon and Ultras. Shin Oni's Hadokens are now already charged, and he has a vicious AI pattern that puts all the other bosses to shame. And they both have normal character health and stun (1000).
 * As well as their Capcom vs. Whatever series:
 * X Men Children of the Atom had the Juggernaut and Magneto.

Juggernaut hits like hell and took a few blows to remember he had a hit stun. Just to put into perspective for people who didn't get it about Juggernaut. Many people argue that he is harder than Magneto, and with reason: In this game, he is a LITERAL JUGGERNAUT. If you wanted to die fast, you just needed to make your Full-special-bar-super-duper-stringy-combo. Juggernaut will take his time to do a full charged attack just because he won't flinch, no matter what. This works for hilarious effect if he starts using his Bum Rush while you are spamming him with Optical Blast at the farthest distance possible; He will PLOW THROUGH THE BEAM and will reach you with enough momentum to cause massive damage.

Magneto's AI is complete bullshit and seeks to royally piss you off at the worst possible time. He has a projectile which has absolute priority, can fly well beyond your character's reach (except if you're using Storm or Sentinel), and has a move which sends four magnetic orbs that home in on you and keep you stunned in the air if they connect. To top it all off, he has two super moves, a trait which no other character has. One of them sends a bunch of rocks flying at you, while the other sends a bunch of energy pillars that cancel all projectiles. Also, Boss Magneto's X-Bar fills up automatically without him actually having to do anything, and will go from empty to full in the span of about 5 seconds, allowing him to use his super-moves all he wants. And he has an energy shield!
 * Marvel Super Heroes had Doctor Doom and Thanos.

Thanos was surprisingly not that hard despite being one of the most powerful villains in the Marvel universe. That said, his moveset has a number of attacks which would make him an outright dickhead to beat if the AI bothered to take advantage of them. For example, his bubble special stuns you if it hits, leaving you open to a deadlier attack. Not only that, but his three most-abused ranged moves are actually NORMAL moves. While you don't have to worry about chip damage, Thanos's super gauge builds like CRAZY, meaning he can catch you with one of his six supers. Speaking of his supers they range from having two stone slabs crush you to death to hurling a miniature sun at you and one which causes Interface Screw. And surprisingly, his supers are a double-edged sword. The AI isn't smart enough to realize that Thanos doesn't need the gem in question to do the particular super. Knock a gem off of him and you're a step closer to kicking his ass.
 * X-Men vs. Street Fighter had Apocalypse, who surprisingly subverted this trope due to him growing to gigantic size and having easily-avoidable attacks.
 * Marvel Super Heroes vs. Street Fighter, on the other hand, had a True Final Boss fight right after Apocalypse - Cyber Akuma/Mech Gouki.

Cyber Akuma is basically Akuma but with a more infuriating AI, completely blown-out-of-proportion-overpowered moves, and a homing Rocket Punch just to add more injury to injury. His fireball/spinning kick/rising punch struck you and you knocked back? His Rocket Punch will hit you just before landing. Because, you know, when you just survived his special attacks, thus, failed to die in a glorious and flashy way, you deserve to be cherry tapped at long range.
 * Marvel vs. Capcom 1 has Onslaught.

He has Juggernaut's invincible bum-rush, can create missiles to prevent you from doing air attacks, has a larger version of Magneto's E.M. Disruptor along with his Magnetic Tempest, can instantly teleport, and to top it all off, he can summon random Brainwashed characters to do his bidding while he sits in the background healing himself. As if all that isn't enough to infuriate you, he has a constant Super Armor effect, which means even when you nail him with a Hyper Combo, he can just counter out of it by using one of his own specials, or worse yet, teleporting to negate a good chunk of your damage!

And just when you think you've beaten him, he grows to Apocalypse's size and takes off his helmet. Now he has Apocalypse's moveset as well, and now has Magneto's Hypergrav stun move and a bigger, more powerful version of his Magnetic Shockwave super.
 * Marvel vs. Capcom 2 has Abyss, who surprisingly subverts this trope somewhat.

He has 3 forms, but they can be easily beaten by following his pattern of easily telegraphed specials and supers. The second form was particularly easy to beat, except when you have an all-melee team... he's bastardly hard, what with having nearly no hit-stun at all and so able to use any of its attacks at you during your combos. Not to mention that if it decided to simply spam green-bubbles-of-death you can do little but get captured and receive its attacks in the ass.

Also, the last form can be infuriating. Of the three he is the least predictable, does the most chip-damage, disappears all the time and has knack of completely vanishing from your screen and attacking from affar, where you can't see which attacks it is doing (and some of them can nearly kill an average character). Or, better yet, he may decide to just get out of the arena altogether and start spamming its ranged attacks from off-screen.
 * Marvel vs. Capcom 3 has Galactus and his two heralds.

First, you fight against Galactus' heralds at the same time, while you can only have one character on at a time, and they have infinite-use supers. However, they share a lifebar.

After they go down, you fight Galactus himself, who has extremely high health and defence, and does a ton of damage with his screen-filling attacks. When the fight starts he'll go easy on you with mildly telegraphed but deadly strong physical attacks, one of which is a finger flick that counts as a Snap Back, wherein your current fighter is booted off the field and another one forced into play, a grab that must be super jumped or button mashed to avoid, and a vicious Megaton Punch. Once he's down to half health, depending on if you wailed on him hard enough, he'll stagger, signifying that he's not pulling his punches and starts using his Power Cosmic on you consisting of various beams. Hilariously his eye laser can be avoided by getting right in front of him, but his other lasers aren't so easy, two of which (A Beam Spam from each finger and an array of beams that cover the screen) have to be blocked if you're not using a character who can fly, and they still cause massive chip damage, god help you if you're using Zero, Akuma or Phoenix who have the lowest stamina in the game. Once you've hit him hard enough he's likely to use a Sphere of Destruction that can instantly kill you if you don't deal enough damage to stop him. Plus, if you lose against him, he destroys Earth (EARTH K.O.).

To make his SNK Boss status even more apparent, the Ultimate re-release allows you to unlock a mode where you can play as him. (And before you ask, it's single-player only, obviously) Put simply, even a novice player has to explicitly try to lose in this mode, which is easier said than done, as he wins if the timer hits 0.
 * Capcom vs. SNK 2 has a subversion in both Shin Akuma and God/Ultimate Rugal, both of them the result of one absorbing the other's powers. Like any other SNK Boss, they're extremely difficult to beat and have overpowered super moves, but they actually follow the same rules that the player is bound by - and they're playable and balanced for human vs. human combat because they take significantly more damage when hit. Their difficulty comes primarily from the fact that the AI will use every dirty trick in the book regardless of what difficulty setting is chosen.
 * And finally, we have Tatsunokovs Capcom's, who has three forms.

In his first, red, spherical form he's happy to spam a jumping hammer strike attack and a buzzsaw special, and in some cases will launch homing missiles to get on your nerves whilst hammering you. He loves spamming his stock-stealing super wherein he exudes a red force field, steals a super stock from you AND crumples your character for a potential free hit. Put simply his first form prefers to Attack Attack Attack.

His second form, the yellow, armed biped form is easier since his attacks are more easily avoidable, even his fire wave super.

His final form goes back to the red sphere, now with a large arm coming out of it. He'll be lobbing meteors and tornadoes a lot, and his supers are a lot more dangerous. One summons a torrential downpour of fire, though he doesn't use that often. Another is a sweeping fire wave, though his final super, grabbing you and blasting you point blank with a fire beam does tremendous damage if he connects it.


 * Gundam Vs Gundam NEXT had Kira Yamato in Strike Freedom (In EX Stage final, where you have to in single player not only obtain a certain amount of points but also not die at all) whom first attacks you in Strike Freedom Form, Then in his Meteor where he gets a set of new moves and an annoying powerful attack that will smash most 1000 class mechs before losing the meteor and enters permanent SEED mode, which mean he can HIMAT burst to his heart's content. He was available in the next update but lacked the Meteor ability and can only go into SEED mode for a limited time. Some people thought he was worse than Devil Gundam, at least he stood still.

Also, his normal attacks are not to be sneezed at, his charge shot is pretty much dyname's sniper beam upgraded to hit you instantly and if you get caught in his melee, he will deliver an 5x Issen followed by Dragoon spam. This becomes painful when you fight against Destiny as well who has level 8 AI to back it up and denies your precious charge shot attacks.
 * WaDom earns the SNK boss award, a constant melee involving its legs, a counter grab. and you gotta kill two of them. Or the stage with Char, Quattro and Sazabi boss stage. Char carves you a new one with his speedy melees, Quattro does you in with its Wave Motion Gun and Char spams funnels and the beam shotgun.
 * Power Stone has Valgas. Aside from the fact that beating him may require several tries with difficulty set to 1 (with a maximum of eight), what makes him so cheap is that not only his grab can make you lose two Power Stones at once, but said stones also tend to bounce out of your reach and right next to him, with him usually entering his Super Mode while you're still getting back up. The fact his One Winged Angel is actually weaker than him (with obvious results: "Final Valgas" can be easily beaten at the first try) shouldn't surprise anyone.
 * Darkstalkers: The Night Warriors has Pyron, an Energy Being made out of fire who will put you on fire very quickly. He's fast and when combined with his teleport can make him very difficult to catch, plus he deals very high damage and has a projectile that takes up a large portion of the screen. When he became playable in the next game he actually didn't lose many of his tools, however.
 * Jedah in Vampire Savior: The Lord of Vampire can be tricky, thanks to his wheel attacks, flight mode and long normal attack range. He also has some incredibly damaging supers and another reason you should beat him quickly. but from the get-go the player has access to just about everything the boss character is capable of.
 * Star Gladiator's Bilstein is one evil bastard in the True Final Boss fight of the game (in which you must get to him from within a specific time limit or else risk getting a false ending). This form of Bilstein, called Ghost Bilstein, is an overpowered and unfair boss (imagine KOF '94's Rugal having the POW Meter maxed out and that it stayed on for the entire match!). His broadsword has a much larger range and that any strike from him can literally shred a huge amount of health from your character. His Plasma Revenge is very brutal and that it can outright kill a character if their health is very low. Also...he can't be ringed-out and that he seems to have a nasty habit in moving around real fast. Lastly...Ghost Bilstein has an exclusive move from within this form in which he summons an unblockable wave of Plasma explosions throughout the entire ring and much like the Plasma Revenge...these explosions can kill your character in an instant if their health is low. By the way...you only get one shot when fighting Ghost Bilstein and that you have to defeat him in order to see your character's true ending. Losing to Ghost Bilstein gives you both an automatic bad ending and a game over.
 * From Megaman Battle Network number 5, Double Team DS, we have Bass XX... with 4000 hp, ridiculously overpowered attacks (his Darkness overload does at least 700 damage!), and a regenerating aura that takes 150 damage to get rid of for just a few seconds, he is EXTREMELY difficult to defeat.
 * In the Asura's Wrath DLC Lost Episode 1 and 2, Ryu and  can be this in the steet fighter styled portions of the DLC on the Highest difficulty and can do K.O.s with just a few good combo's. They are also really hard in the Asura's Wrath styled portion of the game to this extent, too, but only on Hard mode diffculty. It can, however, be made worse with the Mortal Life gauge.

Arc System Works

 * Guilty Gear has Justice. Most of her attacks have long reach, a typical Punch-Slash-Heavy Slash combo could take off a large chunk of health off.

She also has an attack called Gamma Ray which racks up an excessive number of hits, came out near instantly and getting hit guaranteed that you would be dizzied and thusly vulnerable to another blow (Or worse, ANOTHER Gamma Ray if her life was low enough). This attack even does a huge amount of damage if you block it, and she is not above throwing it out after knocking you down, forcing you to block.

And you know her Imperial Ray attack, where she fired a red laser which went across the whole screen in a vertical circular motion? The attack that was a super in her later appearences? That beam which covered a lot of ground and ensured you'd have to stop what you were planning to do and block it, especially up close? In Guilty Gear 1, its a standard special she can spam however much she wants no matter her health or tension level. Not to mention at some ranges, it can fill up her Tension meter in about a fraction of a second.
 * Guilty Gear X has Dizzy, which has the same attack as Justice. Her strength and defense are artificially increased in computer-controlled mode.
 * Guilty Gear XX has I-No, whose boss version has a CPU-only (until Accent Core) move called Megalomania in which the background goes black, a bunch of warning signs appear as I-No sprouts wings, and she fires off a shitload of weird heart-shaped balls that detect movement and rape your health bar if you are unlucky enough to get hit (around 70-80% damage, depending on the version and how many of them hit).

Also, when fighting Dizzy in Story Mode or in Gold Mode, she gains a new super as well, called Hikari no Tsubasa (Wings of Light), where she suddenly becomes naked while laser beams sprout out from her body. This super has 3 versions, one of which is an Instant Kill (in all versions before Accent Core, the screen pops up as SLASH, but in Accent Core it's DESTROYED). Whichever version you get depends on what distance you're at when she enters the crouch stance. If you're very far away, she will attempt to trap you in an inescapable ray of light from underneath as she fires out a circular laser (think Justice's Imperial Ray on steroids). If you're about mid-screen she'll do the circular laser, but it will randomly slow down and speed up. If you're unfortunate enough to be close to her, you get the Instant Kill version where she fills the entire screen with lasers that cannot be blocked.

There's also Gold and Black modes for individual characters, and are a great way to artificially increase the difficulty when fighting the CPU. Black Mode grants unlimited super meter, and Gold Mode's bonuses vary based on the character who's in Gold Mode; for example, Gold Johnny's Mist Finer becomes a One Hit Kill if it connects. Both modes also appear in Story Mode, disguised in the normal palette for the character.
 * The final Mission of Guilty Gear XX Reload features a half-health Ky versus a Gold, Infinite Tension, EX Sol with regeneration. Yeah, that's a fun one.
 * Guilty Gear XX Slash added Order Sol, whose boss form (fought randomly in place of I-no) was not only obscenely fast and strong, but had a CPU-exclusive move called Flame Distortion (basically a chemically-enhanced Dragon Install) that further increased his strength and speed, regenerated his health and gave him an infinite super meter for a set time.
 * Guilty Gear XX Accent Core makes it even worse - it has both Boss I-No and Boss Order-Sol, fought in sequence. Instant Kills are unusable during the fight with I-No, and you can't continue against Order-Sol - lose one set and it's game over. Not to mention that you need at least 10 Overdrive finishes and use no continues to fight Order-Sol after beating I-no.
 * There's also Kliff Undersn. First, his foward+Heavy Slash takes off a good 2/3rd of your health bar. Secondly, Zugaisai now hits 26 times and takes off half of a health bar. Every attack with his sword does an unreasonable amount of damage. Oh, and there's a mission where you fight him as a half health Eddie. Yep, one Zugaisai is all it takes.
 * Arc System Works, the people who made the Guilty Gear games also demonstrate their penchant for adding ridiculously cheap bosses into other fighters as well in Dragonball Z: Supersonic Warriors 2, where you can fight superpowered versions of Cell, Broly and Goku in the Maniac difficulty Maximum mode. They all move twice as fast as anyone else, take half damage from all attacks, do double the damage of their normal counterparts, have infinite ki and possess special attacks that would make their anime counterparts stare at them slackjawed with drool dribbling out.

Cell can summon tons of ki orbs around him that turn into ridiculously fast lasers that home in, has energy balls that never stop and spams a superpowered warp Kamehameha.

Broly uses the huge ki sphere attack 5 times in a row(one is a super in normal conditions) which each one doing as much damage as a single one would normally do, and can fill half the screen with energy blasts faster than most characters can shoot one.

Goku has an oversized Kamehameha bigger and faster than Super Saiyan 3's and can fire two different, seemingly endless streams of ki blasts...one comes in the size of most special attacks with each individual blast and both are homing. He can also use an unblockable grab move across the entire length of the screen. You can only thank the programmers for being merciful enough to not let the AI realize they don't have to charge their ki and only having to fight them one at a time.
 * The Fist of the North Star Fighting Game has a superpowered version of Raoh at the end. Renamed Ken-Oh (After his tyrant persona in the source material), the boss version has all of his powerups active, can Musou Tensei at will, and has a new super which fires a HUGE FUCKING LASER (Basically the true version of Tensho Honretsu or Heaven Command Charge) at his opponent.
 * Blaz Blue, also from Arc System avoids this somewhat as both bosses (Hakumen and Nu-13) are considered generally balanced. However, they (as well as two other characters, Rachel and Ragna) have "Unlimited" versions which fit this trope to a tee, with the exception that they can be unlocked and played.

Unlimited Hakumen's damage output and speed are increased to the stats that he has when in Mugen mode, and his super meter gain is sped up to 3-4 times the normal speed. He is the penultimate boss in most character's Arcade Modes.

Unlimited Nu's drive attacks summon two swords at once instead of one, her Legacy Edge summons out more swords from the gate, her Calamity Sword fires 4 swords instead of one, and she has super-meter auto-gain. She is the final boss in most characters' Arcade Modes. She comes back in Continuum Shift as Unlimited Lambda, with everything stated above and more now that Lambda has more moves at her disposal.

Unlimited Rachel can do Sword Iris without the Lobelias as a requirement, and both it and its super version go in either two ways: one summons four in a row in front of her, and the other one is a delayed strike in which the second lightning bolt tracks the opponent. Her strikers also last longer and she has super meter auto-gain. She is the final boss in Nu's Arcade Mode.

A quick mention must be given that the end of almost everyones arcade mode you have to beat Unlimited Nu. The exception being the two boss characters of the game. On the PS 3 version, the earlier bosses give you bronze trophies. Unlimited Rachel gives a Silver Trophy when you defeat her, and she lives up to the challenge. If you do really well though, you can fight Unlimited Ragna as a Bonus Boss who will give you a gold trophy. Speaking of which...

The worst of them all is Unlimited Ragna, who is always in Blood Kain, is faster, and stronger. And he also has super meter auto-gain as well as his drive moves healing him even more than usual. And Triple Health! He is the True Final Boss of Calamity Trigger's Arcade Mode and the final boss for Hazama/Terumi's Arcade Mode in Continuum Shift.

In the console version's Story Mode, whenever a opponent needs to be more boss-like for story purposes, the game simply gives them an unlimited super bar.
 * The PSP version and 2010 DLC for the PS 3 and 360 versions have Unlimited versions of everyone else!

Unlimited Jin has enhanced Drive attacks that summon up more ice pillars. His normal specials are now the EX versions and all of them freeze you. On top of that, his D Ice Sword fires 3 at once, and his Icecar now has bouncing properties, meaning you can juggle after them now. And his Ice Wave super now fires 2 at once and his Ice Arrow super keeps you in the air longer while he recovers at the same rate.

Unlimited Noel is faster, can fire all 3 versions of her Optic Barrel in succession, fires 3 missiles if the gun hits with Fenrir, fires 5 missiles without bullets with Thor, and her Chain Revolver moves can now be done more times.

Unlimited Taokaka has faster Drive attacks, can chain any move into any other move, and her "This is for the tuna!" super now does 100 hits. Also her Hexa-Edge can now be done in the air.

Unlimited Tager gets wheels installed in his boots, allowing him to run at super fucking fast speeds and able to go across the screen in 30 frames. He also has autoguard against all mid and high attacks while he's running, and his Genesic Emerald Tager Buster sucks you in hyper-fast when magnetized. Speaking of which, his magnetism now lasts for 30 seconds instead of 7. THE POWER OF SCIENCE!

Unlimited Litchi has enhanced versions of her Three Dragons move that move farther and deal multiple hits, and her All Green now makes 3 energy geysers appear.

Unlimited Arakune can now run, is really fast in the air, and when the opponent is cursed he now summons 3 of every bug.

Unlimited Bang has 20 Nails instead of 12, can now autoguard everything with his Drive attacks, and can use his B and C shuriken the same way as his A and D shurikens. All of his special moves except his nails now add to his Fu-Rin-Ka-Zan meter, and his command throws add 4 symbols instantly, as well as the ground version teleporting him a short distance to reach the opponent. And his Heavenly Phoenix goes across the screen. He's basically Continuum Shift Bang but with benefits.

Unlimited Carl becomes slower and takes a LOT more damage, but in exchange Nirvana becomes hyper fast, does not drain health when under Carl's control, and has enhanced attacks.
 * The upgrade to the console version of Continuum Shift changed every Unlimited character from Calamity Trigger. And Continuum Shift Extend also adds even more movesets to these already horrible characters (seen here).

Unlimited Ragna no longer has triple health, but he still has his godly movement speed and his other attributes. To make matters worse, any attack that involves his sword now drains health like his D moves. He also has a new followup to Dead Spike to make it more useful, which can be easily comboed after his Hell's Fang followup for massive damage. But none of that compares to the worst part about him - he can do Devoured By Darkness without meter. Extend gives him a Distortion drive where he launches towards the enemy in an attempt to grab them For Massive Damage. He is the final boss in Jin's and Hazama's Arcade Modes.

Unlimited Jin is pretty much the same except with the new freezing system, certain moves can freeze multiple times, some as much as 10. His Arrows of Ice super now has a Yukikaze followup afterward, and speaking of Yukikaze it now comes out regardless of whether it countered something or not. Extend allows him to use his Ice Arrow distortion (plus the auto-Yukikaze) mid-air.

Unlimited Noel now has the old versions of her supers as regular moves, and Thor shoots the normal spray of bullets before the 5 missiles. Extend gives her a new distortion where she dashes on her opponent, and if she hits, she'll blow them up.

Unlimited Rachel fires out 3 Lobelias from her cannon instead of just 1. She also has her old Sword Iris back from before which goes in a random pattern. And her Tempest Dahlia now fires out even deadlier objects than before and does not depend on the Silpheed gauge. Extend gives her a homing Sword Iris-esque distortion that doesn't consume her Lobelias at all.

Unlimited Taokaka now has a new special and two new supers. One of them summons a bunch of Kaka kittens to stampede upon the opponent, and the other throws a series of objects at the opponent. All of her attacks that can be charged are now unblockable when fully charged, and do an insane amount of damage. Her projectile-throwing moves throw 3 objects at the same time, and the bowling ball she throws with the C version of the move doesn't disappear until it goes offscreen and can combo opponent endlessly if it hits a grounded opponent. Her Drive attacks have a much slower startup and thus are much harder to combo and can't be aimed to as many directions but they move much faster once they actually begin and if they connect, do absolutely ridiculous amounts of damage and can kill any character in 2-4 hits. Extend gives her yet another distortion where a Kaka kitten will bring a bomb and try to stay close to the opponent until the bomb goes off.

Unlimited Tager is the same, but Gadget Finger no longer requires the opponent to be knocked down. His drive attacks and 6A can also be charged, and his Astral Heat is now performed with 1D, as well as his super which is 1C. His super-fast magnetic projectile now consumes only half of his magnetic gauge instead of all of them. Extend gives him a Megaton Punch as a new super.

Unlimited Litchi is a unique case, as her play style is completely changed. Her teleports and stuff from Calamity Trigger are still here, but she now has a new Chi Gauge instead of using 6B to charge up her moves. Extend allows her to use her Chi attack Distortion at close range rather than at a distance. She can also parry with 1D.

Unlimited Arakune has a new super move which summons a bag of insects. If the opponent hits it, small red bugs pour out of it, and if the opponent touches any of them, they are instantly killed (complete with an amusing 5-second snippet at the end of the normal Astral Finish theme, which fittingly enough is the part which says "until the world is covered in Azure"). Also, that new Fever Mode gauge he has is now a thing of the past, as he now curses instantly like old Arakune. Extend gives him a stronger version of his crawling special move as a distortion.

Unlimited Bang borrows the 3-hit command combo and teleport from Chipp Zanuff. He now also has a multi-hit aerial auto-combo as a new super.

Unlimited Carl is exactly the same as before. Extend gives him one of Relius' supers.

Unlimited Hakumen is completely different from before in that he has actual changes. All of his specials now cost only 1 magatama (not his supers), Enma can be canceled, the dash preceeding it works much like wavedashes in Tekken in that just inputting the motion causes Hakumen to dash, it can be done repeatedly, pressing A at a precise time gives performs a better version of Enma which is faster and can be jump cancelled and neither it or Enma itself cost any magatama to perform, all of his counters end in Yukikaze or Tsubaki, his actual Yukikaze comes out instantly like Jin's, and as a bonus his version is both invincible and unblockable during execution unlike Jin's which is only unblockable, and his Shippu now does multiple hits and stuns the opponent for a long time if they block it, leaving them open for Yukikaze if you have the meter to spare. Extend gives him a new all-kick autocombo super.

Unlimited Lambda is another unique case in that technically it isn't Lambda. When you attempt selecting her Unlimited form, you'll find that it's none other than Nu. That's right, the bitch is back, and worse than ever. She is exactly the same as original Unlimited Nu, except with the added moves from Lambda and more cancel fun. Although it sounds lame, it actually makes her cheaper than before. Extend gives her a new autocombo super.

Unlimited Tsubaki is now the new Calamity Trigger Unlimited Hakumen. She has literally no changes except that she now has a Quick Charge function like Order-Sol (her technical predecessor) and charges her Install quicker. Extend gives her a diving attack as a new super.

Unlimited Hazama is about 3 times as fast as he is normally is and has super meter auto-gain, as expected. What isn't expected is that he has a green force field around him that, if you get caught in it, drains your health and adds it to his. Extend also gives him a new Distortion where he grabs then flings his opponent all over the screen with his Ouroboros. He is the final boss for most characters in Continuum Shift. The console version changes him up a bit in that all of his specials which require a certain move to be performed before it no longer require it, he has a new kicking move (a weaker version of Jayoku Houtenjin that still fatal counters), and his command throw leads into a stronger version of his Mizuchi Rekkazan.

Unlimited Mu has an exclusive super which is a carbon copy of Dizzy's Imperial Ray super from Guilty Gear, and the Attack Drones that she summons can now move freely and fire at will. And you can also continuously summon as many as you want, essentially making the battle a Bullet Hell shmup. Extend allows those attack drones to cause Collision Damage, and Mu now has two more Distortions: One is a grab-range distortion and the other one fills the screen with electric orbs.

Unlimited Makoto is unique in that the majority of her movelists has been changed. It's a combination of Dudley's and the other Makoto's moves. The one thing that makes her broken, however, is her new 100-heat super, which makes you mash B in order to get OVER 9000 damage! Extend gives her a multi-punch auto-combo super.

Unlimited Valkenhayn has a new battle stance where he waves his arms around similarly to Magneto. He starts out unable to transform into a wolf, but once he transforms he can pretty much infinitely switch in and out of wolf form with impunity, and he also gains the ability to use his wolf transformation to escape many normally guaranteed combos, much like Bursting, but not limited in the number of times he can use it per round. His Beast Spiral can now be done 6 times in a row just by mashing A and it automatically homes into the opponent, and he has a new Spinning Piledriver super which always does a fixed amount of damage and can be easily comboed after latter. And now he also has an aerial-ramming super.

Unlimited Platinum can choose which one of her Magical Weapons she wants to summon next (instead of the order being randomized with the ability to see the next one in the row), and they're always the powered-up versions she normally only gets after using a Distortion Drive to power one up. She has a new DD that breaks 3 Guard Primers on block, more than any other move in the game (besides Arakune's Astral Heat, which doesn't really count), and her Cure Dot Typhoon summons a colossal cat missile followed by a rain of cat bombs if it connects. Extend gives her a short range super which attacks upwards.

Unlimited Relius has an infinite Ignis gauge, meaning he can use his puppet whenever he wants. He also has two new supers. One of them is a high-damaging variant of Venom's Dark Angel from Guilty Gear (a fireball super, and he can fire two rapidly if his gauge allows it), and the other is an instant autocombo with Ignis.


 * And ArcSys has done it again in Battle Fantasia with its end boss, End of Deathbringer (like the original, except constantly ) Though he lacks a Super Move meter, his lone super-special attack, Apocalypse Flame (activated after an unpredictable countdown), almost completely fills the screen, and will burn off a large chunk of HP to anyone who hasn't mastered Gachi counters. This, of course, is provided you manage to survive his regular special attacks, which deal a lot of damage and have insane priority. And unless you go into "Heat Up!" mode, you won't be able to cause anything but chip damage to him. Also, half of EoD's moves are unblockable and make him immune to stance break (ie, you can't knock him out of them), and on top of that, his Apocalypse Flame can be comboed into, which basically spells instant death if he does it. For all that Arcana Heart 3's Parace L'sia (another boss done by Arc System) is incredibly cheap, she's got nothing on End of Deathbringer - at least she can be hurt with normal moves and hit out of her own attacks, and her lifebar is normal. This... monstrosity... on the other hand, is completely and utterly unfair to anyone who isn't a master. And even to the masters, too. For an amateur, beating End of Deathbringer at anything above the easiest setting is wishful thinking.
 * Persona 4 Arena, has two.
 * The first is Final Boss Shadow Labrys, who is basically regular  on steroids and with a new Persona called Asterios. Her playstyle is described as "simultaneous attack", meaning she's like Carl from Blaz Blue.
 * If you make it through all 12 fights of Score Attack, which features beefed-up "boss-like" versions of every character, you fight a special 13th opponent in the form of Elizabeth and Thanatos from Persona 3. To start, her meter regenerates constantly, and it does so at a near-instant rate, meaning she can constantly spam supers and whatnot. Two of these supers are instant kills. To make matters worse, her Awakening super, only usable when below 30% health, fully heals her like Gill, and since she constantly has 100% meter it is guaranteed to always happen. Last, but certainly not least, like everyone else she has an actual instant kill technique. Hers is a counter that works on what seems to be every single type of attack including projectiles, grabs, supers, and even other instant kills. This serves as a warning to those who try to play keep-away with her.

Namco

 * Heihachi in the first Tekken is much harder and faster than his later incarnations, due to being the boss of the game. This has been written into canon with Tekken Tag 2 supposedly featuring a return of his younger self, when he was much tougher.
 * Tekken 5: Jinpachi Mishima (unavailable to players), who can interrupt any attack you throw at him and possesses a fireball that takes away two-thirds of your health with a single hit (which he can also fire rapidly in case you try to sidestep it). Yes, the final boss of a hand-to-hand fighting game is best known for his nigh-unavoidable magic stun and long-range fireballs.

If you are jumping in the air, the stun will drop you down to the floor and you will reel from it. If you are as far away from Jinpachi as the game will allow, the stun will hit you and you are unable to move. If you are blocking, you are stunned and unable to move. If you are on the floor, the stun will hit you, make you stand, and have you reel.

Also, there's one thing that gets you no matter what - The stun/fireball combo. Go go, random stun counter followed by avoid-this-or-die fireball. Both mechanics are fine on their own, but when combined, there's nothing you can do.

Ask any Tekken player you know how bad would it be if you couldn't move for six seconds, given that Tekken's claim to fame is juggling and combo-ability. Then add to the fact the weakest of Jinpachi's moves will take off a fifth of your lifebar and is combo-able. And you have the equation for a true SNK Boss.
 * Azazel, the literal Dragon of Tekken 6, is much worse than Jinpachi. He's got Devil's Eye Beams, Jinpachi's stun, plus even more ridiculous moves such as raising boulders out of the ground, throwing barrages of ice projectiles, and the ability to regenerate. Not to mention he doesn't even stagger on normal basis, and when it happens, he takes no damage. May be the Grand Champion of SNK Bosses.
 * The Bonus Boss NANCY-MI847J has ten times the energy bar of other fighters, cannot be stunned or juggled, attacks with lasers, machine guns, and missiles, and has an Eye Beams attack that cuts holes in the floor, killing you instantly if you're standing there.
 * Boss Jin, whom you fight before Azazel, and right after Nancy. At the start of the round he automatically activates Rage Mode, meaning he deals twice the amount of normal damage. Not only that, but his AI suddenly increases to that of an expert player, no matter if you're fighting the CPU or a ghost, and will counter your strategies at every turn.
 * Tekken Tag Tournament 2 gives us a three-stage Boss Rush featuring the return of young Heihachi and Jinpachi Mishima at Stage 7, Ogre at Stage 8, and finally fan favorite Jun Kazama for the Final Stage.

The first two stages are warm-ups for the battle against the latter. She starts off as nothing special, save for a few dick moves on her part which entails using her Attack Reversal every now and then, which is considerably rare for Tekken AI. Since she is a solo fighter, her entire health bar is doubled and must be depleted to knock her out, including her recoverable health. Once you win the first round and defeat Jun, the fun begins...
 * ...and Jun transforms into Unknown, effectively ending the decade-long debate on the character's identity. Unlike her Tag 1 incarnation, she does not mimic other cast members a la Mokujin. Instead, she retains Jun's moveset as well as gaining a damage output increase and a few boss-exclusive moves that borderline on downright unfair, including a call back to Jinpachi's infamous stun. There are no guarantees in this fight; if she wants to, she'll either initiate a simple combo that shaves off roughly half of your health or reverse your attacks to death. One of her most dangerous attacks is a Snap Back-esque move where a portal appears on the ground. If you get hit by it, a huge hand surfaces from the stage and splats you, forcing you out of the arena and leaving you with only a pixel of health remaining and a large chunk of recoverable health. Did we mention that she can combo into it? Good luck when she pulls that off.
 * The first game in the Soul Series, Soul Edge/Blade has Soul Edge, who would later become Inferno. He is a much tougher version of Cervantes who is able to teleport and use flying unblockable attacks, seemingly from anywhere on screen. His difficulty is so great that the original arcade version of the game had to have its difficulty lowered for a rerelease, because him and Cervantes (who you face before him) were considered impossible to beat. It can still take several retries to defeat him and that's only if you're lucky, as he's utterly unpredictable. And note that "lucky" here means you happened to not be in the way when he used one of those flying attacks and he launched himself clear out of the ring.
 * Soul Calibur II makes use of this trope with Inferno, a final boss who uses random move sets of other characters. This final fight carries the deceptive appearance of a single-KO battle, but Inferno's life bar is in fact 3 times normal size. He also receives a damage bonus, a special throw that knocks off more than half of your life gauge, and changes move sets when he hits 2/3rds and 1/3rd of his total life (and if you deal extra damage, it always truncates it, so Inferno starts each "round" with that amount of life). Additionally, flames blanket the stage and cover Inferno's body, making it harder and harder to discern his movements. Definitely a joystick-snapper.
 * Soul Calibur III utilizes this to a degree even with non-boss characters, although there are certain moves that can be used to circumvent the seemingly precogniscent AI. But the secret boss, Night Terror, is absolutely batshit insane in this regard, with Eye Beams and a stance which renders him immune to damage; unless you're using one of the aforementioned AI-killing attacks (or a few more that take advantage of Night Terror's absurd size) it appears that you can only beat him if the CPU decides that you can. Oh, yeah...you can't beat him by "ring out", either, because he'll just fly back in. Thanks God he isn't playable, at least if you're not using a cheating device.
 * The story mode only character Ceres is supposed to be this - he blocks pretty much every move you use against him, and the story moves on if you lose the battle. Beating him results in nothing.
 * Soul Calibur IV actually averts this, believe it or not, with its final boss, Algol. While he's fast and strong, he never feels impossible, and his projectiles are not only blockable but they can be parried to reflect them back against him. In the Tower of Lost Souls mode, he actually does appear to fight like an SNK Boss, until you figure out the bug in his AI. In the right circumstances, he'll ring himself out, every time those circumstances are presented to him.
 * In Tower of Lost Souls mode he has a 50% chance each SECOND of "unblockability" - which includes being impossible to parry - being granted to his next attack, takes 30% normal damage, does double normal damage, has two health bars, and drains life with every attack? Essentially, if he hits you the battle is probably lost.
 * The Apprentice in Arcade. While not -quite- SNK level, he does seem to have an uncanny knack for sidestepping verticals, vert-jabbing horizontals, air-juggling and... to cap it all off... a truly ridiculous frequency of Just Impacts.
 * Soul Calibur V has the honored privilege of granting us not one, not two, not three, not four, not five, not even six, but seven SNK Bosses, all fought in a row, in Legendary Souls mode. This, ladies and gentlemen, is the new Score Attack. The AI becomes demonically possessed, reads your inputs and reacts with unbelievable timing, and does not let you so much as breathe when it goes on the offensive. It can also perform any move requiring a Just Frame perfectly, resulting in combos which are completely impossible unless you have godlike timing.
 * First up is Kilik. Despite being a mimic character normally, in Legendary Souls he is stuck using Xiba's style, which was originally his own from previous games. The second you let him get momentum, he starts comboing you like a maniac with ambiguous mixups, and doesn't stop.
 * Next is Nightmare, who uses an exclusive costume just for this mode, his Soul Calibur IV outfit. With his immense range, he will constantly knock you down and take away about 50-70% of your health bar using his Brave Edges and comboing into his Down+A+B attack while you're on the ground, resulting in a special command throw.
 * Your third opponent is Siegfried, who also uses his Soul Calibur IV outfit exclusive to this mode. While he doesn't have the damage output of Nightmare, he does have the momentum of Kilik, and is also a massive block-whore. Be prepared for ring outs several times over, and good luck trying to break his defenses.
 * Contestant #4 is Cervantes, decked out in his Inferno costume from the very first game. While he's a bit easier than the first three opponents, your jaw is guaranteed to drop as he juggles you with Instant Geo Da Rays / Psycho Crushers.
 * After Cervantes, you fight Edge Master. Just like Kilik, in this mode he gets stuck with one set style - Alpha Patroklos', who in turn uses Setsuka's style. All of his moves are extremely fast, and since the AI is demonically possessed he will pull off extremely difficult and impossible juggles and combos that nobody has ever seen before. For many, this is the breaking point, but there's something even worse after him.
 * That "something worse" is the 6th battle against Elysium. Again, she uses a set style - Pyrrha Omega's, to be exact. And this just so happens to be Sophitia's style, who Elysium takes the form of. Unfortunately, this version of Sophitia's style is faster, and about 10 times cheaper, making Elysium a total bitch to fight against. She spams Nemesis Step like it's going out of style, and deals insane damage. She will also use her exclusive Critical Edge, which is a 20-hit full-screen attack, at the worst possible moments. Have fun.
 * Your last opponent is a familiar face - Algol from Soul Calibur IV. This time he's gotten smarter and doesn't ring himself out on accident anymore, which is bad news for you. Luckily, he's easier than the first 6 opponents put together, making this an Anti Climax Battle.

Midway/Netherrealm Studios

 * Midway's 1997 War Gods on Nintendo 64 features two SNK bosses in the progressive fighting mode: Grox and Exor.

Grox was the first big green blob thing, who looks like a joke but takes basically no flinch damage when hit and has a variety of moves which take 15-30% of your health in 1 hit.

Exor's name is not even given, and he basically has a bunch of moves no other character can perform, others that no other character cannot perform efficiently and also takes no flinch damage, combined with teleportation abilities and a very high speed. Even on the lowest difficulty, this boss is impossibly hard.
 * The Mortal Kombat series is notorious for its SNK-like sub-bosses, starting with Mortal Kombat 2s Kintaro and ending with Mortal Kombat Deadly Alliances Moloch. Not only are they super-powerful, but they're unthrowable, unjuggleable (for the most part) and - with later games - immune to projectile attacks.
 * In Mortal Kombat, we had Goro and Shang Tsung.

Goro had the highest defensive and attack stats of any character in MK 1, and his stomp could get heavily annoying. He also had an unblockable fireball that came out very fast, and an overpowered throw that did almost 40% damage.

Shang Tsung also had unblockable and cheap fireballs, and could morph into any character at random, including GORO! If he just so happens to morph, the character's AI will be at the maximum level, meaning it'll be extremely difficult to land a hit. He's also floating along the ground so sweeps and Sub-Zero's slide special will not work on him.
 * Then came Mortal Kombat 2, which introduced us to Kintaro and Shao Kahn.

Kintaro is basically Goro but taken a step further in difficulty. His fireball is slower, but still unblockable. His stomp is more easily telegraphed, but now it has a shorter version which stuns you for a LONG time.

Should you beat Kintaro, you go on to fight Shao Kahn. The first thing you'll notice is that he has a head start at the beginning of the round, and overrides the "FIGHT!" message from appearing with his taunt (since he's the announcer after all). What differentiates him from the previous bosses is that all of his moves, when blocked, put your character into hitstun, and have no lag time inbetween. The only way to defend against him is to dodge his attacks, which is easier said than done. He can throw an energy spear, ram you with a shoulder charge, Sparta kick you all the way to the other side of the screen, and throw a mean right hook that also sends you the same way.
 * Mortal Kombat 3 decided to drop the traditional 4-armed Shokan sub-bosses in favor of Motaro, a demonic Centaur. He easily outshines the previous sub-bosses in cheapness, and is the grand champion of SNK Bosses in Mortal Kombat. Projectiles thrown at him bounce right back at you, he teleports like crazy, his attacks (throw included) do WAY too much damage, and he can fire an infinite number of energy balls from his metal tail in any direction. You'll need an extensive knowledge of your character's bread-and-butter combos in order to win against him (or you can crouch the whole time and uppercut every time he gets close enough - he'll tail swipe you a couple times, but not enough to put you in danger).

Should you beat him, you will have to once again fight Shao Kahn, but this time he is much different than before. This time he's really pissed off about your defeating him in MKII, and can now utterly destroy you in a few seconds. He button-reads, he's faster than he was in MKII, does more damage while taking less, traded his energy javelin for an unblockable Eye Beams, has an upwards version of his shoulder charge in case of jump-ins, and he can pull out a giant metal hammer which automatically dizzies you regardless of whether you blocked or not. "It's official: You suck!"
 * Mortal Kombat 4 didn't offer anything, but Deadly Alliance gave us Moloch, a blue oni that acts like a red oni, with Glowing Eyes of Doom and a ball-'n-chain strapped to his hand. He takes roughly half-normal damage, and has ridiculous attacks such as a non-telegraphed bum-rush. The worst thing about Moloch is if you win one round against him, he just stands there and roars. If you want the satisfaction of seeing him fall, you need to win the match.
 * Mortal Kombat: Deception introduced Onaga, the mighty Dragon King, for the first time, and he lives up to his name. The game foreshadows Onaga's immunity to projectiles in the opening cutscene: he walks through sustained fire from Shang Tsung, Quan Chi, and Raiden at the same time.

First off, he's bigger than Goro, Kintaro, Motaro, and Moloch combined. Secondly, he breathes fire that causes massive hitstun. Third, he's immune to projectile attacks, and while he can't crouch, his guard is both high and low at the same time. Fourth, he can use his wings (which are even BIGGER than his body) to backdash away from combos, while doing some of his own. And fifth, his throw is really powerful, and cuts off about 40-50% of your health. And if that wasn't enough, the stage where you fight against him has a Death Trap (the spikes surrounding the arena) which you can't knock Onaga into, but he can knock you into it.
 * Finally, we come to Mortal Kombat: Armageddon, which gives us the fire elemental Blaze as the Final Boss. Some of you may remember Blaze as the fiery-looking secret character from Deadly Alliance. Yeah, that version's gone. Instead we get a giant lava titan that can do a rolling attack, teleport, and do overpowered combos.
 * Shao Kahn retakes the throne as of Mortal Kombat 9.

The main thing that makes him a pain in the butt is his ability to turn off hit stun on himself whenever he pleases. So you can just punch him as much as you want but you're still eating a shoulder to the face. All the bosses seem to have this property but Shao Kahn certainly makes the best use of it. He can also fling his hammer at you, which is unblockable and has a considerable hit stun. And God help you if his X-Ray attack hits you, though, since it does 54% damage. Oh and all the damage he takes is reduced by 50%, effectively doubling his lifebar. Overall, a very challenging boss at least and SNK Boss at worst.

And things are even worse in the Challenge Tower, where you fight him a bunch of times. Some are just straight one-on-one matches (though you don't get to choose your character), but most stack things against you even further, such as making you go solo against Shao Kahn and two other opponents, or go solo against three Shao Kahns on one lifebar.

Other Commercial Fighting Games

 * Mighty Morphin' Power Rangers: The Fighting Edition has Ivan Ooze: he's unaffected by gravity, can't be thrown, has a normal attack which knocks the opponent clear across the screen if not blocked, his other moves (3 normals and 2 specials) are all projectiles, with the specials being multiple homing projectiles, and one of his specials makes him invincible for about 2 seconds. So what's supposed to offset these advantages? He can't block, and he has no super. Too bad his invincibility special more than makes up for not being able to block, and his specials do so much damage that he doesn't need a super. And the Revive Kills Zombie part of the trope is, in fact, subverted, because the player, when he manages to play as him, gets all the same advantages and disadvantages. Arguably one of the most broken fighting game characters of all time in fact.
 * Alpha-152 in Dead or Alive 4, a superpowered Kasumi clone made of... something (Jello? Cool Mint Listerine? Semen?). She's unplayable and has a unique move set including combos that can take down 2/3 of your health in one shot; even on "Easy" difficulty she takes serious players multiple attempts. She also has the annoying tendency to teleport out of your combos and launch into one of her own. She also has a very annoying throw that can instantly kill you where she holds you down and then launches you into the explosive floor of her stage.
 * Certain characters have an easier time fighting her than others. It's been too long to remember exactly which characters, but if memory serves, quicker characters and characters that are difficult to read (Helena, Brad) had an easier time, as they can adjust to her teleport attacks quicker, not to mention the ability to just rush at her and get a few moves off before she teleported again.
 * She doesn't suffer from SNK Boss Syndrome, no; she revels in it. It's so bad that when she reviewed the game on X Play, Morgan Webb openly threatened @152's AI's programmers with bodily harm should she ever meet them in person.
 * Before Alpha, there was Tengu in Dead or Alive 2. He returned in 4 as a balanced secret character, but in his original debut game he was a bastard. His AI was almost completely omniscient and would counter everything. His moves did tremendous damage, yes, but he had one move that skyrocketed him to boss territory: he charges up and creates a giant gust of wind around himself, knocking the opponent away. He would do this move all the time, and it was also unblockable.
 * Tengu was actually really easy to beat if you learned his weakness: while the wind-gust maneuver cannot be blocked, it can be countered via the middle-punch counter, so long as you are somewhat close to him. The gust has a long wind-up time, giving you plenty of time to close the gap. What's more, Tengu loves spamming the gust when you're at range. So just counter the gust, back up so that you provoke another gust, run up during the wind-up and counter again, back up some more, etc. With this technique, you can easily beat Tengu with any character. Yes, exploiting the AI is cheap, but then so is Tengu.
 * In the Updated Rerelease, Dead or Alive 2 Ultimate, he gains a new CPU-exclusive move for his exclusive stage which cannot be accessed: he can change the weather. It's really distracting and it can hurt your eyes if you're not prepared for it. And while he's doing this he can charge at you freely.
 * After Tengu, Ayane's foster father Genra/Omega made his debut in Dead or Alive 3. First, you fight him in a really weird camera angle. Secondly, the fire around his stage makes everything super-blurry so you can't see his attacks. Finally, one of his attacks has to be jumped over, which is easier said than done.
 * Not to mention - trying to use a throw on him lowers YOUR health. Also, if he gets hit and falls, he unleashes a short flame wave, which takes some of your health, if not blocked.
 * This all falters in the face of Dead or Alive: Dimension's brand new "Tag Challenge" mode. It starts off innocuous enough, but the final five fights have you play against a beefed-up Kasumi clone named Kasumi Alpha, all of the bosses in Dead or Alive history, AND a brand new boss in the form of  Add to everything that they take majorly reduced damage and can take away up to 75% of your health from an accidental tag, and the fact that you have two characters to even the odds barely matters.
 * Bushido Blade 2 has, if the player plays the story mode as a Shainto clan character, a penultimate boss that instantly teleports away, without a scratch, if 'hit'. The only way to kill him is to keep making him teleport, as each time he does, he reappears closer and closer to the player, and you have about a second-long window to gut him before he stands up and readies himself. Of course, if you die (which is easy, since your character is a potential One Hit Point Wonder) the process starts over. Almost as if to make up for this pain-in-the-ass opponent, the Shainto's final enemy is an unarmed girl who doesn't even fight back.
 * All characters, Shainto or not, eventually have to go up against someone armed with a gun, while the player has only a melee weapon. The guy with a gun was in the original Bushido Blade as well, and had this irritating tendency to backflip away if the player got close. The trick was simply to run around until he'd fired six times. Guns need reloading, swords don't, and his defense is pathetic. But be warned. The first time you fight him, he will Just Shoot You.
 * Matrimelee, the revival installment of the Power Instinct series, replaces Angela with a not even less 'cutie' Princess Sissy. A seemingly harmless young girl, she can conjure many different things from her magical box. One of her most annoying tactics is constantly bringing out Abubo from Rage of the Dragons that swings his fists around, so they would get you in both air and ground. She regularly does this when the opponent is anywhere nearby her. This guarantees that you will be unable to get close to her unless you keep trying incessantly, are a pro and/or exploit her rather simple AI. But it doesn't end on Abubo. She also has drill chainsaw boots, a purple bomb, an uncancellable frog projectile and even a booby trap spike sword. And, to finish your attempts to marry her off once and for all, Sissy's arsenal includes a FUCKING annoying and unblockable super where she shoots a raygun at you and turns you into a FROG. ...oh, and she's almost unhittable when she attacks.
 * On a side note, she's still damn hard to beat even if you're playing at the easiest difficulty. Yeah, even as Sissy. And even in Bloodlust Fight mode.
 * Groove On Fight has Bristol, the final boss. His first form is fairly harmless - does high damage with leg-based attacks, but nothing too terribly nasty. Then he turns into a demon after being K Oed. And things get worse, as he gains a slew of attacks that have incredible priority, come out monstrously fast and do entirely too much damage. His Super is unblockable as well. And he buttonreads. Welcome to hell.
 * Super Smash Bros Brawl's Adventure mode did an acceptable job with bosses, right up until the last one,  He has moves that do an insane amount of damage, can teleport, usually right before you get to him after recovering from said attack, has an insane amount of health, and has a move that some Street Fighter players might recognize from Gill. It looks exactly like his Seraphic Wing attack, and it does the same thing - instantly kills you (though you can avoid it if you dodge three times in a row, expertly timed and all). (This attack is officially called "Off Waves".) It's interesting to note, though, that all of his attacks bar the latter come from the Kirby character, Marx. At least you get SIX lives/characters in Subspace Emissary to tackle him.
 * However, Sakurai had to be a bastard. In Boss Rush mode, you only get one life. Good luck beating it on Intense, as per one of the challenges that can't be bypassed with a Golden Hammer.
 * Sakurai: "(laughs)"
 * European player: "(laughs some more)"
 * It is worth noting that in Boss Rush mode, the bosses are toned down from the same difficulty equivalents of Subspace Emissary mode. That is, fighting Tabuu in Intense in SSE is even harder than doing it in Intense in the Boss Rush mode. This is because of the aforementioned extra 'lives' thing you get in SSE.
 * The difference is not in difficulty, but in length: all bosses do pretty much the same amount of damage in SSE and Boss Rush, but they have a LOT less HP in Boss Rush.
 * The Eternal Champion, from the obscure-but-popular Genesis Fighter Eternal Champions. Not only is he as strong as him being on this list would imply, you have to beat him five times in one round, and each time he uses a different (but equally painful) move set.
 * And if you were lucky enough to get ahold of Eternal Champions CD, the Sega CD version, you had to do it not once, but twice. Then you also went up against the Dark Champion, who had the same annoying multiple-self-resurrection abilities, complete with moves relating to natural disasters with which he just wouldn't let up at all. Oh, and that's without mentioning the fact that the computer in the last game can ignore the game's rules by spamming their special attacks, despite having an apparently functional "Inner Spirit" gauge, which was thankfully taken out in the second game. The Champions in particular like to repeatedly Insult you, destroying your ability to use special attacks while using their own invincible-ground-sweeping abilities... over and over and over.
 * Getting to the final set of fights on Champion mode leads to the Dark Champion kidnapping the Eternal Champion. You get to fight the Dark one as the Eternal one in what can be an absolutely epic fight, were it not for the Dark Champion being damn hard.
 * The worst part is you only get one chance to win the last battle, or you have to start the whole game again.
 * From the Arcana Heart series:
 * Mildred. In her first form (from story mode), you have one round to beat her or lose. She doesn't actually move, but she effortlessly attacks you from across the screen with massive knockback attacks that are undodgeable (but, fortunately, not unblockable) and has an insanely high defense -- if you can actually manage to get close enough to damage her beyond projectile chipping. If you lose against this form -- which is essentially inevitable if you have a character/arcana combo that has useless projectiles or none at all -- you get a second form where she has access to all the best moves in the game, (including giving her regular special moves that are supers for anyone else that uses them) she has a dangerous new super that does nearly half a health bar in damage if not blocked and hits the entire screen, she has mid-air and ground recovery that instantly leaves her standing up on ground level, she starts with a full super meter and she has a defense nearly as good as the first form. Oh, and you can't win via time-out. Otherwise, she Of course, you can avoid this just by setting the game timer to infinite. A catch, though: if you do beat the first form, you instead get... the exact same battle, but the boss starts out with an empty super meter instead. Long story short: if the Mary Sue trope could be applied to an SNK Boss, Mildred would be A-number-one on the list.
 * Arcana Heart 2 gives us the somewhat less frustrating Angelia. In arcade mode, she simply plays like a smart computer opponent (including her annoyingly effective but technically sound "Halo Dash->Halo Super" tactic) and doesn't seem to use her arcana at all... but she still doesn't seem to have charge her halo dash attack, since she can and does use it constantly (especially during attack clashes). In Story mode, on the other hand, she uses the same tactics, but her arcana (Mildred, incidentally) is always active, meaning Mildred launches attacks on her own pretty much independently. In addition Angelia also has a certain unavailable-to-players super where she... drops a building on you. Seriously. Needless to say, it's unblockable and does over half a health bar of damage, though she thankfully only uses it infrequently.
 * In Sugoi! Arcana Heart 2, players can use Angelia's building drop super. Also, in Story Mode, there is a new hidden boss named Parace L'Sia, who makes Mildred from the original look like a gigantic joke. She fires projectiles with reckless abandon, has absolute priority on all of her moves, regenerates damage, and most of her supers are a One Hit Kill! One of her supers is a projectile that if it connects will, after about five seconds, suddenly deal insane damage and put you into hit-stun - even when you're in the middle of a combo or blocking a multi-hit attack. Just to make things worse, she continuously regenerates her super meter, and has another move where she goes into a cocoon to accelerate its regeneration. The cocoon move only ends when her super meter is completely filled (at nine stocks) or if you attack the cocoon enough times to break her out of it - and none of your attacks will do any damage during this time. And she's still regenerating her health. She goes well beyond a typical SNK boss and acts more like a overpowered horrible MUGEN character.
 * Arcana Heart 3 tops it off with first having you fight mid-boss Scharlachrot, who plays like Hazama with robot tigers that fire beam spam cannons. To wit, she attacks really aggressively, her Arcana (said robot tiger) can interrupt your combo by shooting you in the middle of it and set her up to combo you (and it will happen often). One of the Arcana supers are to fire a super powerful bullet capable of wiping out nearly 50% of your health, and her Arcana Blaze is to fire a frigging huge beam that goes upwards and will take out 50% even in chip damage. Oh, and beat her on the first round and she goes to activate PERMANENT Super Mode with boosted attack and defense. And did we mention that her Arcana bar usually regenerates in an unusually fast rate so you'll find yourself often facing that near-50% health powerful bullet? Win against her? Then prepare to fight Ragnarok, a Humongous Mecha bent on destroying Japan and plays differently from the rest of the game on a 3-tiered battlefield - if you do not understand how to fight bosses like Onslaught, you're pretty much done for, and his main offense are two annoying flying funnels that constantly fly around you and interrupt your acts, not to mention Bullet Hell gallore or a beam rain unblockable. Much like Mildred, this is Do Or Die - run out of time and Japan gets blown sky-high. In short, the final boss is essentially made (overly) difficult not by its moves or its strategy, but by the fact that it basically converts the game into a side-scrolling platformer, while you're still saddled with the control scheme of a fighting game. If the spam attacks don't get you, the clock will simply run out while you're trying to jump up and hit that last weak point.
 * And if that wasn't enough, Parace comes back in the Score Attack mode of the Arcana Heart 3 console port. The good news is, she doesn't do nearly as much damage this time around (no more one-hit kills, at least). The bad news is, she doesn't need to because now she teleports around the arena like she's on crack, and can (and will) do long combos that will take out a huge chunk of your life! Worse, her AI is even more aggressive than before and she seems to button-read as well, since nearly any attack you do will be met with a better one that will set you up for a long combo. Fighting Parace in this game is like fighting Rare Akuma. The only good thing about this fight is that if you actually manage to somehow hit Parace, you'll find she takes more damage than usual, but she still has auto-regen for her health. Its safe to say that Parace manages to take this trope to Serial Escalation levels, and considering most of what SNK themselves does with their bosses, that really says something.
 * Battle K-Road claims "Super Real Fighting". And who do you fight at the end of this game which features takedowns and such? A bear. Yes, a bear. Named Mr. Bear. Who has a Dragon Punch. And can knock most of your life off in one hit. Where's Tekken's Paul Phoenix when you need him...?
 * Similar is Fighter's History Dynamite's hidden boss: you fight...an ox. And like Mr. Bear he'll likely stomp your rear end.
 * Greed from The Rumble Fish. The game and the character have to be described before going further. In The Rumble Fish there are two main gauges, Offense and Defense. The Offense gauge fills up as you attack, once it's maxed out you can initiate an Offensive art. You can also do Advanced Attacks, which takes half of the gauge and allows you to extend a combo. The Defense gauge fills up passively or by blocking attacks and Defensive arts are initiated from said gauge. It also allows for Impact Breaks, which is basically a counter, for half the gauge. Once both gauges are maxed out, they merge and become the Critical gauge. That allows for Critical arts, which are really strong super moves. Greed's Offense art allows him to combo his special moves into another one for a short period of time. Once you encounter him in Story Mode, he's just like his playable version. Until he literally Turns Red. From that point on, his gauge turns into the Critical gauge and is in a permanent state of his Offense art. Cue the SNK Boss: He can counter any of your attacks if he feels like it, combo from said counter with an Advance Attack and shell out a lot of damage by chaining his special attacks. Oh yeah, and he can also chain his Critical art from his specials. And if you corner him, he can just Wall Jump his way out to safety.
 * Dural, in any given Virtua Fighter. On one hand, it still counts if you beat the game without defeating her, but if you want to see the good ending, you have to win, and in 4 you only get one shot.
 * The Dynasty Warriors series' Lu Bu averts this trope in the same way that modern Akuma does -- he's an example of That One Boss, but the only gameplay aspect unavailable to players is "hyper mode," which is not exclusive to him.
 * His AI in DW3 is actually worse than average: while he knows to use his first charge attack to make you stumble, almost every time he waits so long to attack you again that you can recover first. (Then you need only have low health for free Musou and the victory.)
 * In Dynasty Warriors 4 they also start his incredible weakness to arrows (they murder him). This actually extends to the AI where in one situation he actually turned away from the player controlled max level Zhao Yun to brutally murder a random body-guard that shot him in the back of the head with an arrow.
 * Warriors Orochi series seems to make Lu Bu's AI even stupider. In the first game, he can easily be tricked into giving up Red Hare, and any decent player should have the cavalier up high, making your basic attacks against him pretty good. In the second he's worse as he will start laying into the Redshirts following once you've dismounted him, stolen Red Hare and given him distance. He'll use up Musou on these guys before coming at you.
 * The prototype of all 2-D Fighting Games, Karate Champ. Once a player reaches 8th Degree Belt level, the computer-controlled opponent becomes practically unbeatable, anticipating and countering a player's every move with frequency only a literal god of fighting could be expected to pull off.
 * Mike Tyson's Punch-Out!! ups the difficulty to ludicrous levels for the fight against the eponymous boxer--a single punch from the guy KO's you, and his weak spot is only exposed very rarely. Not to mention he acts lightning fast, giving you very little time to dodge and fight back. And there are no saves.
 * When Punch-Out was re-released in the 90s, it replaced Tyson with a sprite-swap named Mr. Dream because Nintendo's contract with Tyson expired. His AI was replaced, too, but not in the good way. This was the version released on the Wii's Arcade.
 * The Retraux remake of Punch-Out for the Wii does not have Mike Tyson (obviously, considering several controversies), but it has something even better. Mr Sandman also seems to have carried over Tyson's mannerisms for the fight against him.
 * Chaos from Dissidia Final Fantasy is a great example of this trope. He attacks faster then any other character in the game by a wide margin, his attacks massively lower your Brave and increase his own, he chains his Brave attacks into his HP attacks, and while most of his Brave attacks are "melee", they send out shockwaves that exceed the size of the area where you fight him. When he uses Divine Punishment and Scarlet Rain, once he starts the attack, he becomes invincible. His Demonsdance attack chains together a massive string of bonecrushing hits, with several HP attacks in the combo! He also gets the Shinryu summon, which, unlike the player's summons, can be called as often as Chaos wants and his effect varies, because Shinryu mimics the other summons in the game! And he also has three forms, fully recovering HP each time while you're left at the amount you had. There's a catch, though: there's a flaw with his AI that makes him unable to avoid the final hit of Sephiroth's octoslash HP attack, he'll dodge every slash except the one that actually does the HP damage, so if you feel like going slow and steady against him, you can turn even his Inward Chaos form into a joke.
 * The second game features  as the penultimate boss of the story mode's extra scenario, he defines unbelievable, most of his attacks have huge hitboxes, making them difficult to avoid, only one or two don't crush your guard. As if that's not enough, in a game where 9999 damage is the most you'll ever be able to do, he has 60 THOUSAND HP, and naturally, you can't use any of your items in the gateway you encounter him in, so cheaping out is impossible. His HP attacks drain your EX-gauge to emptiness, so using it is diffuclt. The real kicker comes after you finally manage to beat him,   you have to fight him again, this time he has more moves, an assist, and 125 thousand health! (ironically, this form is actually weaker because he doesn't have as much defense). To top it all off, He's unlockable. And in a frustrating case of The Computer Is a Cheating Bastard, has all of the same limitations as a player character usually does, and more (No assists, ex gauge, and brave constantly depletes until you get abilities that fix that).
 * General from Taito's Kaiser Knuckle / Global Champion / Dan-Ku-Ga VS. a Guilty Gear XX champion from Japan. Even SSFII Turbo's Shin Akuma isn't comparable to him.


 * Ohga from Technos Japan's Voltage Fighter Gowcaizer is bastardly.

He has absurdly quick recovery time. His basic special moves consist of a very damaging triple uppercut, a teleport that causes damage if your character is in his path (and you will be), and a Kaiser Wave-esque projectile. This projectile is quite large, and can only be blocked or jumped over; attempting to cancel it out with your own projectile will cause it to burst into five seeking fireballs. Jumping over it also leaves your character to be a sitting duck for his triple uppercut. And his defense points are bigger than any normal characters and he may even do a sweep-triple uppercut combo which may as well take 80% of your health. Ouch.
 * Rumble Roses. When you play through the story mode of any character, eventually you fight someone called Lady X. Which looks like a woman in a pantsuit with a metal mask and metal gloves. While she's obviously strong, has strong moves and is hard to humiliate (yeah, that's part of the game); she's not overpowered. Then when you beat her, the pantsuit comes off... and you realize it's a cyborg. Now Lady X Substance is suddenly way stronger and almost impossible to humiliate... and can do weird cyborg stuff. She has unique moves that other characters couldn't do as they involve her upper body turning 180 degrees, her fist can detach from her arm and let her do a ROCKET PUNCH... and here's the worst part: All characters have "taunts" which build up their special meter a little but cause no harm to the enemy. HER taunt involves her body turning around like mad (and playing an alarm) and she quickly runs around the ring. If she touches you, you fly off with HIGH damage... and all you can do is avoid her. AND the taunt fills her meter completely.
 * You get a few seconds to step out of the ring when you see her preparing the taunt.
 * Young Toguro is the final boss of the generally substandard Yu Yu Hakusho: Dark Tournament, and has powers to match. Bear in mind that the previous fights were against very strong characters, but ones with normal restrictions. Toguro has insane speed and power, about a two-head height (and therefore a very large reach) advantage, a three-kick counter, and at least two combos that can put you down in no time flat. Both include low blows, forcing you to block while crouching - a difficult position from which to retaliate. And once you deplete his first health meter, he powers up with a second one and becomes much more aggressive.
 * Dragonball Z: Budokai 2. Dragon World mode and Kid Buu, who among other things, was pretty much unblockable.
 * It got worse in Budokai Tenkaichi. Kid Buu has a Blast 2 move which is a long and crazy combo with nasty priority that the AI LOVES to spam in BT 2. Then there's Android 13, whose super form has a normal Blast 2 that is XBOX HUGE, there's Broly who is surprisingly fast for a huge guy, Syn Shenron/Omega Shenron/Yi Xing Long, whose attacks have vicious priority and worst of all, Cell, who is just plain horrible.
 * In Budokai 3 Kid Buu not only gains an Ultimate Attack, but the new Ki system means he starts with 6 bars (whereas you generally start with 3). And to top it all off, to unlock Uub, you must fight him down to 1 bar (difficult itself on later difficulties), then go back to Kaioken or base form (unless you'd been fighting there the entire time. Again, difficult), and THEN use the Super Spirit Bomb technique and WIN the power struggle. Note: If you lose the power struggle, he dies anyway. And you don't get Uub.
 * And that's not even to mention Uub vs. Omega Shenron on the hardest difficulty... or Omega Shenron in any of the story modes, for that matter. "30 Seconds to kill him AND do it using my Ultimate Move? WTF?!"
 * Mutilator from Bio F.R.E.A.K.S. It's a bit like fighting Metal Gear Rex, only it's a Fighting Game. And the arena is flooded. And the water is full of sharks.
 * Final Boss Gaara from Clash of Ninja 2, who, among other things, could not be staggered. No, not by any hit. No, not even then.
 * Then, in Clash of Ninja Revolution 2, we have Kabuto as the final boss. He staggers. SOMETIMES. He'll usually knock you out of any combos, and even when you DO make him stagger (usually a low or high attack does it) he'll Substitute out of it, THEN combo YOU! Also, not mention he has a Healing Factor, which is actually normal, but the fact that he can't be staggered DRASTICALLY increases the effect of it, since usually the amount of HP he can recover goes down upon waking up from knockdown. Also, you need to finish him with Rasengan, which is hard to hit with and surprisingly weak.
 * And Kabuto again in Ultimate Ninja 2. Fucker heals himself, stays out of your reach and god help you if you're using Kakashi, who as of the game's storyline, is unable to use any of his ultimate jutsu.
 * And then we have Deidara from Clash of Ninja Revolution 3. You play as One-Tailed Naruto, which sounds like it should be easy, but it's not, because you're health goes quick and Deidara likes to spam his bug "art", which does a lot of damage. And if you're on hard mode, prepare to eat your Wiimote. And unless my copy is glitched, you have to beat him WITH your Ultimate, which means you have to be close. If you kill him with any thing else, you still lose! Damn it Deidara!
 * In Naruto Shippuden Ultimate Ninja Storm 2, we have surprisingly, the Boss fight with Kakuzu, and the last phase of the boss fight with Pain:

Kakuzu starts off relatively easy, but then he goes One Winged Angel, and you have to be able to reach up to him while he's attached in between two trees, while he's spamming projectiles, like wind blasts, fire balls, and tentacles made of his Earth Grudge Fear bloodline that pop out of the ground really quickly, then finishes off with a Fire and Wind combined technique that's basically a Humongous LASER that can do a severe amount of Multi-Hit damage if it hits. And the fact that it takes much longer is more Dragged out than the other boss fights before it shows how hard it is. Unlike Pain, who's supposed to be hard as a final boss, Kakuzu's Surprise Difficulty also makes him That One Boss.

For Pain, the full amount of difficulty really starts to show. Pain is now in full awakening mode, but to tap it all of, because Bosses have infinite chakra, they can spam Substitution Jutsu as many times as they want, as a Substitution bar didn't existed until Generations, and unlike the previous boss battles, he will take advantage of this. His attacks also do ridiculous amounts of damage, and his AI goes up several times in level regardless what difficulty the AI is set on. He gets even harder when you loose Sage Mode, and your attacks start doing less damage.
 * The final opponent in Naruto Shippuden Ultimate Ninja Storm Generations, in Killer Bee's story, is Kisame, with +100 attack. This roughly equates to all his attacks having the strength of an Ultimate Jutsu. Your best bet is not to let him hit you at all. And don't think you can relax once you've gotten his health down to 50%: his Awakening is... nasty, to put it mildly.
 * In Daraku Tenshi, you get the wonderful chance to play against two powerful bosses. First, you've got Trigger, who has a gun. Keep in mind that only ONE playable character has a projectile, so just dealing with him alone can be a pain. And finally there's Carlos, who has a huge freakin' sword that can kill you in three or four hits alone. And if he hits you with his super, it's basically instant death. Yeah, did you know that people who worked on this game went to work on King of Fighters 99-2003? Not surprised?
 * Rouge from Ranma 1/2: Battle Renaissance on PS 1: Not only do her attacks have priority, but she has two degrees of a normal special attack where she flings countless projectiles at the player along the entire vertical axis. These WILL carry you up and back across the entire screen. Good luck surviving long enough to even get back into attack range.
 * Asura Blade has the sub-boss, Curfue. The best way to describe him is Cable on massive steroids and crack. He's got a laser rifle, grenades, a combat knife and at least two sidearms, and he uses them all to horrifically great effect. On you. A typical battle with Curfue is not unlike playing Do Don Pachi - there's so many lasers, bullets and apocalyptic explosions rocking the screen and turning you to ash, you have trouble figuring out what's going on. As if the chaos wasn't enough, Curfue's most damaging move must be blocked low or it'll wipe you out, and he's got a massively damaging close range grab that can take off nearly half your health. And he can use his super attack in midair, too, which is bad since it has no startup and comes out of nowhere.
 * Kron, the final boss of PSX Fighting Game Cardinal Syn, is a particularly ruthless example. The final form of the game's Big Bad, Syn, Kron is a freaking huge dragon who, in addition to sporting ridiculously powerful attacks (fire bombs, anyone?), possessing the ability to fly, and being so huge and powerful she takes much less damage than any other character, she also has a one-hit kill move (in which she bites the player character in half) which she tries to utilise quite frequently. Also, the stage in which you fight her has an infinite time limit, which means that the player is unable to be a cheap bastard by simply getting a few hits in and staying out of her way until the timer runs out, out of pure desperation.
 * Even worse, Kron can be unlocked as a playable character. And when she's unlocked, the player can face her in any play mode. Including Survival Mode. In which she's just as frustrating to fight as she is in Arcade Mode. Yup. Just try getting a good Survival win rate when you're facing her.
 * Bloody Marie, the final opponent of Skullgirls. She can't block and she can't move while over 50% health, but she has permanent super armor, meaning her attacks don't stop even when she's hit, she can't be grappled and soaks damage like crazy. But the worst is that, when very low on health, her hitbox becomes minuscule, to the point that you can't hit her with most standing attacks and specials, which is a very big advantage for her since most of her moves are good anti-airs.
 * Metal Sonic of Sonic The Fighters will grind you into the steel floor of his stage. Faster and stronger than regular characters, his grab involves dropping you from the air to take out a little more than a quarter of your health, and he even rips off M. Bison's Psycho Crusher for devastating effect. Think you can cheese your way past him by breaking all of his barriers? Doing that only pisses him off to the point where he spams the aforementioned Psycho Crusher (which is unblockable, by the way). Makes it all the more satisfying when you achieve Super Sonic and smash his face in. Robotnik? Anticlimax Boss.
 * Oh, yeah, and he has an attack that takes off half your health in a single strike.
 * Interestingly, Robotnik (or "Robotonic" by the intro) actually has some devastating moves, as evidenced by using a cheat device to unlock him. His status as an Anticlimax Boss may have actually been a case of AI Stupidity. This is explained as being because Robotnik has never used this particular machine before, so he doesn't know the controls yet. You also have only 15 seconds to beat him or you get a Downer Ending where the Death Egg blows up with you inside it. They had to make him a joke in order for it to be possible to win.

Not Fighting Games

 * God Hand does this when you fight yourself in Stage 51 of the Fighting Arena.
 * In the original Advance Wars, the final "boss" CO Sturm is an unlockable character to use in Versus mode. His units do more damage (though they have weaker defense) and his CO power makes a meteor smash onto the largest concentration of units in a 5x5 diamond shape, which does 8 damage (out of 10). Versus mode Sturm however has a greater defense and less attack power, and aforementioned CO power does just 4 damage.
 * In Advance Wars 2 Sturm now has an insane defense as well as insane attack power. He is either banned or tag teamed played in 2 vs 1 matches.
 * Though oddly enough, his units receive a larger move penalty when it's snowing than any other CO does. However, since there's only one CO (Olaf) that has this as his powers and the COs you take into the final battle are determined by certain conditions and not by choice.
 * You could choose who you take into the final battle in Advance Wars 2 (the game where Sturm is really, really cheap, but still). And for the weakness to snow, since 1) the only CO able to use that (Olaf) is not one of the strongest or easiest CO to use (to say the least) ; and 2) the snow will bother your troops as well...Let's say that's not a painful weakness for him.
 * Star Wars Battlefront Elite Squadron: at least in the DS version.
 * Various RTS games face a campaign only "boss" unit, or the enemy has some special thing(s) that is unique to the campaign.
 * In the original Command and Conquer, the temple of Nod at the end of the GDI campaign can fire multiple nukes during the mission. This is compared to the nuke silos players can build, which fire one nuke and can never be used again.
 * Tiberian Sun: Firestorm has CABAL's army fought in the last mission of both campaigns. CABAL fields mostly Nod units, but also includes Cyborg Reapers which can render most infantry helpless and make for mean anti-materiel weapons. Once you've finally wrapped up the multitude of bases that span the entirety of the very large map, CABAL himself is guarded by the titular Firestorm defense system (think "literal firewall"), which in a rare instance of smart villainous planning holds its power source within the 'Wall. Take that out and CABAL deploys the Core Defender. It can shrug off your Ion Cannons with little effect, can kill anything in two shots or less, and will completely wreck your shit unless you're prepared for it. Its one weakness is the aerial option.
 * In Tiberium Wars: Kane's Wrath in one mission you will face up to 3 MARV Tanks, two of them at once. Players can only build one MARV unless they capture a Construction Yard of an opposing GDI faction (it has to be a different GDI faction, not just any one mind you). Inverted during the final mission, where it is possible to build 3 Redeemers, but it's highly unlikely that you'll use them since the level is going to end one way or another at that point.
 * You can build 2 MARVs but not in the campaign. In the Global Conquest mode, as GDI you can deploy the most powerful army, which will include a MARV by default. During a mission, you can build another MARV. You can't keep the second one beyond the mission, however. This applies to all epic units.
 * Inverted in Red Alert 3 in the Japanese Campaign, where you are given control of the nigh unstoppable Shogun Executioner, who is basically the bigger brother of the King Oni Battlemechs that can heal when attacked by tesla weapons (guess what weapons your opponent use?), has an AOE shockwave attack, kills any units in one hit, and is so huge and well armored that simply walking into an aircraft will destroy it. To quote Moskvin:"YOU... CHEAT!!!"
 * In Tiberian Twilight's final Nod mission the final 'boss' is the enormous Arcus Bomber. In the introductory cutscene it eliminates your allies' Crawlers and can obliterate most of your forces with just a few shots. Since the game unlocks more advanced units as the player gains experience, the player may not yet have access to the only units powerful enough to do any real damage making the game impossible to complete without spending hours player multiplayer and Skirmish mode games in order to unlock the necessary units.
 * Blizzard had something of a fondness for super strong units in Warcraft III. First case is in the final level of Orc campaign where you face off against Chaos Orcs - essentially your own units with far more impressive stats, and a unique damage type that does full damage to everything. The final level of the Night Elf campaign pits you against an Undead enemy that cannot be conquered and fields units that players normally cannot control, in escalating numbers. Among them are Infernals, which are immune to magic and deal damage to all nearby units every second, and Doom Guards, which while weaker then Infernals are still stronger then any ground units you can field. The computer will also send hero units with some unique abilities at you, most notably Archimonde, who alone is capable of tearing you apart. Thankfully, he only shows up in the last couple of minutes and your task is to merely delay him. Incredible stats, unstoppable skills, and Divine armor (only vulnerable to an attack type normally found in high level creeps). In the unlikely event you can kill him once, he has an item that revives him with full health and mana.
 * This was kind of the trend after Warcraft 3: Reign of Chaos, where the campaigns would always end in some overly powerful boss that was a modified unit. Not surprisingly, this eventually gave way to WoW, whose MMORPG style basically makes this mandatory for it's Raid Bosses.
 * The original campaign in Warhammer 40000: Dawn of War had you fight a Deamon Prince at the end, who was way stronger then even the game's unique super units.
 * And in Dawn of War 2, the extension Chaos Rising tops it with a, a Damage Sponge Boss with devastating attacks and that can see infiltrated units.
 * King Famardy in King of the Monsters 2 (which, surprise surprise, is made by SNK). He is ridiculously huge, moves very fast, can use the projectile attacks of every other bosses in the game and he is the only one that can hurt your character simply by touching you, whereas being touched by the others bosses would atleast locks you in a random but potentially successful grapple.
 * Midas from Agarest Senki. Doesn't play fair with his Limit Break meter. Has attacks that one-hit kill all characters in a 2-cell radius, too much HP, regenerates health at an absurd rate. Has a Limit Break that can guarantee a Total Party Kill if you party isn't spread out far. And did we mention you fight him halfway through the game, before many of its Game Breakers become available?
 * The final incarnation of Rahu in the Gamecube Custom Robo. Takes single-digit damage from nearly all weapons, moves fast enough that it can't be hit unless standing still, does ludicrous damage with his main gun that can't realistically be avoided unless you use one of the four pieces of cover in the holosseum, AND recovers instantly from all knockdown effects. That last one is the worst, because in this game, recovering from knockdown grants a few seconds of Mercy Invincibility. Rahu gets all the benefits and is immune to the stun time normally associated with knockdown. Even outnumbering it three-to-one your chances of victory are slim. God help you if it decides to focus its attacks on you.
 * "God help you"? No. You WANT Rahu to come after you. If he doesn't, he'll stomp your allies, and when he does finally come for you, you'll be powerless to stop him one-on-one. At least his attacks CAN be dodged (as difficult as it is).
 * Kingdom Hearts's Bonus Bosses often edge into this, due to their abhorrent attack power and incredible speed. One of them even has attacks that bypass the abilities to stop instant/combo induced death, this is all made much worse by the rest of the game's relative ease, making sure the player's blindsided by the Difficulty Spike.
 * The North American and later revised Japanese releases of the first game feature Sephiroth, whose attacks not only come out fast and hard, but also has absurd range. His Heartless Angel brings you down to one HP and depletes your entire MP gauge. Unlike some other bosses, he can actually use one of his desperation attacks before he actually gets desperate which is basically his version of an Omnislash. You can only hope to block it, or if you have near superhuman reflexes, dodge each and every strike with absolute precision. His actual desperation attack, Supernova, can hit you from anywhere when he actually throws it at you, and it can't be blocked. During his desperate state, he starts pummeling you with spinning strikes which he whips out immediately after coming out of a teleport, and it's almost always behind you. And when he does so, he leaves behind a wall of Shadow Flares. Some argue that this version of Sephiroth is the hardest incarnation yet.
 * In KHII, he uses the Omnislash-like attack more frequently, especially to stretch out the part where it's his NORMAL ATTACK. Unless you've leveled up your Drive Forms up to this point, be prepared to eat a lot of Heartless Angels because he friggen floats out your range when he powers it up this time around. When he gets desperate, he goes so far as to actually SLIDE BEHIND YOU when he attacks. He also tends to poke you by quickly gliding around the arena and then smacking you. Lastly, his Reaction Command attack, while easy to see coming from a mile away, going so far as to start every bout doing it, do NOT get hit by it. It will hit you from anywhere and everywhere, so be sure to have your feet planted firmly on the ground because you CANNOT block it in the air. However, the real hammer on the nail is the fact that even though Goofy and Donald are explicitly present before AND after the battle, they are completely absent during it, so no Drives or health refills.
 * Then there's KH Final Mix's Unknown/Xemnas, who bashes you with swift and powerful strikes and uses a multitude of powerful spells that will absolutely demolish you and he is almost always constantly doing so. He can suspend energy bolts in mid air while, after a second, come at you in a rapid fire fashion, generate large energy orbs AND can guard against your attacks by putting up a large shield which can also damage you and knock you back. He also has an attack where he places a unique status ailment on you that will gradually drain your health unless you use the proper command when prompted to. You will be doing quite a bit of rolling around until he bothers to actually give you an opening.
 * KHII Final Mix has two of these, unfortunately. First up is the full Roxas fight. Unlike the playable version of Dual Wield Roxas, this guy is completely batshit insane and uses his real powers to their fullest.. His standard attack combo consists of him constantly shifting left and right as he attacks and before you have a chance to immediately counterattack, he jumps right back and comes at you. After recovering from any attack, whether or not its a combo, he will retaliate immediately by jumping in the air and coming at you with you a rolling attack that will track and hit you, no matter how far you are. He also has his own version of the The End Reaction Command and if you can get it, you can snag his Keyblades from him to amp up your attacks. The catch however, is that he'll actually become even more aggressive and start throwing friggin laser beams at you until he manages to steal his Keyblades back from you. But at this point however, he'll start buffing his attacks with constant beam attacks in varying patterns. Not even getting into his desperation attack, he has another attack where he constantly spams Strike Raid while constantly buzzing around you. And it hurts. A lot
 * Oh gawd...the Lingering Will is an absolute nightmare. This is the only superboss in the entire series who CANNOT be knocked out of his attacks and at the beginning of the round, he's usually flying all over the place at high speeds at which Sora can't even hope to match. Invincibility frames on every attack he does. They all involve his Keyblade taking on a multitude of forms and they come out quick. Even when he's running straight at you, you can't hurt him. At all. Your only bet is to hit him after an attack. He has actually has an attack that breaks him out of any your combos by immediately countering with a whip attack which you cannot get out of. He has two variations of a magic seal attack that either seals your attack or magic commands, forcing you to hit LW a number of times to break out of using the command that wasn't blocked. And then there's his desperation attack that requires a specific set of maneuvers to perform to survive it, because it's not only lengthy, it's pretty much guaranteed to kill you. And the best part: His number of health bars span the size of the longest possible gauge in the game, surpassing even Sephiroth.
 * If you thought the Lingering Will was bad, wait until you fight Vanitas Remnant. While he has only one bar of health, be very very prepared. He has an absurd amount of defense and even if you managed to max out your character, your combos won't be doing a lot of damage like on other bosses. He is basically a souped-up version of Vanitas at the end of Ven's story, his attacks do fatal amounts of damage, usually almost one hit kills, even if you've leveled up excessively. He also has a new attack where he encases himself in an invincible sphere and launches shadowy versions of himself at you which fly quickly at you and deal insane amounts of damage and if you get hit, you'll be inflicted with Blind which obscures your line of sight almost entirely. Don't even try to use Cure spells, because he will go right ahead and do he same, so actual potions and exlixirs are essential. Like an actual SNK Boss however, he's not very smart and will blindly run into Mine spells without changing his path.
 * And then there's the other secret boss introduced in the North American and Japanese re-releases, the Mysterious Figure. Drop all of your uberpowerful commands and spells in favor of quick ones that offer invincibility frames because this guy will ruin your day hard. Everytime he is in motion, running or walking, he is constantly warping and darting around, so forget your Shotlock. Instead, don't use Shotlock at all because he actually has access to the Heal Block command which transfers any usually incurred damage into health. He has a long combo not unlike Xemnas, but it is far far longer and it WILL deplete your health to zero, unless you have the Chance abilities equipped. He also has access to a projectile version of Tornado that will literally blow every command in your immediate deck out of your body, forcing you to try and pick them back up while he finishes you off. Gets even worse when he jumps into the air and throws out an energy whip. If you get hit by this, you will assuredly die because not only does it almost take out almost all of your health in one sweep, he will not hesitate to spam it over and over again, AND it negates your Chance abilities. Aside from his Beam Spam attack and Doom attacks, he has the annoying ability to actually recover bits of lost health by turning back time if he gets hit by a powerful attack. And then when he actually gets desperate....
 * In the JRPG Dragoneer's Aria, to get to the Earth Dragon, you have to Battle against Ruslan L'avelith. While fighting against him, he can easily kill your entire team. Once you beat him and he joins your team, he's nerfed like hell.
 * Fire Emblem Thracia 776 is already the hardest Fire Emblem game in the series (or heck, it's probably the hardest game in existence!) Then along comes Chapter 22, which has several factors working against you as it is. Once you cross the second bridge, however, the first one collapses, and the mini-boss, Reinhart, starts attacking you. He has Daim Thunder, a weapon normally only available to Olwen, which allows him to attack twice, and has FOUR skills: Continue (randomly allows him to attack twice in one round) Ambush (ensures that he attacks first no matter whose turn it is), Duel (forces another round of combat without allowing the unit that just attacked a chance to heal) and Big Shield (will randomly block one of your attacks entirely). With all these power-ups, it is literally and completely impossible to beat this asshole without resorting to status effect wands, which are rare. Silence keeps him from using magic, so you can thankfully use ranged attacks against him (he also has a Brave Sword) but the most reliable way to beat him is to put him to sleep, and yet both options are only achievable with a M-Up wand or a Holy Water, since your wand user must have higher magic than he does, and all stats except HP cap at 20 in this game! Reinhart's mere existence might just cause your file to become unwinnable if you don't have Warp wands, which most people use to kill the real boss on the first turn (He also has Big Shield, so good luck with that!) and warp Leaf to the castle and seize it for an instant win, but then you miss out on the chapter's other goodies. In fact, the first house on the map gives you a Warp wand, as if to say, "Yes, you dumb fuck, that's how you're supposed to clear this chapter." To add insult to injury, you have to have the above mentioned Olwen talk to him to obtain a rare weapon.
 * Then there's Medeus on Lunatic Mode in New Mystery of the Emblem, who takes "blatantly unfair" Up to Eleven. He has all his stats maxed out, which equates to:
 * 99 HP (the most you can ever have is 60)
 * 40 Strength (more than anyone on your side can ever have. Combined with his 20 might weapon, he has an attack of 60. The highest possible defence you can have is 30. 60-30 is 30. That's the bare minimum damage he can do. Now go back and read what the most HP you can ever have is.)
 * 40 Skill (meaning a base critical hit rate of 30%, i.e. only a maxed out Luck Stat is enough to totally negate the chance of a critical, and a critical WILL kill you, no exceptions.)
 * 30 Speed (by far the worst of the lot, this means he'll double attack anything up to and including Heroes [26 Speed] and looking at the previous points, you should be able to put two and two togeather. Yes, NOTHING can possibly survive 2 hits from him, meaning anyone with 26 or less speed who attacks him is already dead. )
 * 40 (actually 42 due to Geo Effects) Defense and 30 Resistance (not the worst thing about him, maxed out Marth still hits 21 damage with the Falcion. Everyone else on the other hand...)
 * Furthermore, he has a range of 2 spaces, meaning not even Archers are safe and any Staff users trying to heal a melee attacker will be in his attack range. Oh, and did I mention you have to deal with him AND 20 odd Bosses In Mook Clothing at the same time??
 * Magic the Gathering: Duels of the Planeswalkers 2012 (a game based on a Collectible Card Game) has Karn. While most of the cards you can get for your decks can be described as "strong, but fair", Karn has cards in his deck culled from the Legacy ban list. God help you if he uses a Mox to Tinker for Darksteel Colossus on turn 2... your only response is pretty much Counterspell. Or concede.
 * The final fistfight with General Kim in the true ending of True Crime: Streets of LA.
 * Starting in Armored Core Masterofthe Arena, the Armored Core series would include a boss AC called Nineball Seraph. Most up to the point you meet this thing, all enemy A Cs are simply A Ied controlled versions of A Cs you could build yourself if you really wanted to (except for an end boss in Project Phantasma, but Game Breaker machine gun made the thing a pushover), but Nineball Seraph is constructed entirely from parts you can't use. The thing is extremely fast, and has way more armor than an AC for its speed would allow, really strong machine gun arms that both have laser blades (if you use gun arms you can't have laser blades) that have a higher attack rate than yours, since it has two, and a couple of back mounted homing missiles that are very accurate and really hurt. For added speed it can transform into a birdlike mode that makes it even faster, though in that state it will only use its missiles. No matter how you build your AC, this will have you heavily outgunned and kill you a few seconds, even though your armor is fully restored before you fight it.
 * Kioh Gyoku's Final Boss is entirely unfair. Muse, as a playable character, is one of the best characters in the game to begin with. But that wouldn't be epic enough, so the designers did horrible things to her stats. The increase to her defence is at least understandable, since the AI sucks and she'd have killed herself before the battle really started if it hadn't been increased, but they overdid it to the point where the fight with her takes longer than the rest of the story mode combined. But the real problem is that her attack ranks are increased, with her non-boss attacks at 12. Which is a serious problem, since, at that rank, her level one attack basically requires you to stream it across the entire screen to avoid it, and will most likely guard break you if you screw up. Which you probably will if any of her other attacks are on the screen. The fight basically comes down to hoping and/or praying that she dies before the AI Roulette decides to use that attack a third time.
 * Dynasty Warriors Gundam 3: Knight Gundam at the end of the story mode. Assuming you're using a fully-upgraded and customized suit with a high-level pilot, you will still do only minimal damage to him, and he can kill you in two hits from any attack (that's if your defense stat is higher than 350... otherwise he One Hit Kills you). Also, Knight Gundam is one of those Gundams with a "Super Mode" that he enters into after using an SP attack. Except for this battle... he's in his Super Mode for the duration of the fight, and it never runs out. Good luck.
 * In the Katawa Shoujo fan game, Katawavania, after defeating Lillycula, you go up against her older sister Akira. Akira can frequently Flash Step around the arena, often behind you, with little to no warning, has several attacks that are difficult to avoid (such as homing missiles and a beam rifle that can only be dodged by sliding at the precise moment it fires), and has virtually no telegraphing or pattern. The second ending indicates that the creator was not expecting many people to defeat this "unfair" boss.
 * The Disgaea series usually averts this, as with the Absurdly High Level Cap most bosses are just the same as highly leveled and well equipped normal enemies; they're tough, but the follow the same "rules" as everyone else. Even some bosses where you must lose to advance the story can technically be beaten if you don't mind a Nonstandard Game Over. But Disgaea 4 gives us the DLC battle with Baal; he has the power to get a free attack on your characters from any distance as soon as you remove them from the base panel. Since he's incredibly strong, this means he can literally kill your entirely party before he even gets a turn. They just die as soon as you try to use them.

Doujin Fighters/Fan-made Games

 * Eternal Fighter Zero, an otherwise very balanced doujin game, has Kanna as the final boss. Her melee attacks have immense range and her projectiles are fast and cover a lot of area. Her AI is also incredibly skilled at blocking attacks, making it difficult to land any normal hit. Her character is available to the player as well, without any nerfing at all, which is why she's banned from tournament play.
 * Kanna's only banned because players acually use the insane damage, comboability, and priority of her attacks, whereas the AI only defends well. Unknown, however, has been a source of frustration, as she (in her boss mode) takes full advantages of her moves' invincibility frames and spams high-priority projectiles that do almost as much damage blocked. (Thank god for the fact that you can't be chipped to submission in this game.)
 * Super Cosplay War Ultra's Zenka, based on the (in)famously badass Sanger Zonvolt, has full screen specials, supers and EX Super (some of them unblockable or do massive chip damage), high priority, is much faster than her range would imply and tends to exploit these advantages to the fullest.
 * Next, comes Zmega, based on Rugal Bernstein, but in Story Mode, he's weaker than what you'd expect from a Shout Out to one of the greatest SNK Bosses out there. Still, the game plays it cruelly in that there's only one round against him: should you lose, you automatically lose the game, but given the stand in Zmega's difficulty compared to Zenka, it's rather relative. However, this trope applies to his form taken at the end of Battle Royale Mode called Shin-Z, so much that even if you have an allied CPU still standing to fight with you, his sheer tendency to combo his specials directly to a super absurdly well, no thanks to crazy priority, turns frustration and keyboard breaking Up to Eleven. Should you lose against him, you have to engage a survival battle against 5 enemies first before he pops out again.
 * Finally, in comes Alpha, based on The Four Gods from Super Robot Wars. The True Final Boss in Story Mode, Alpha carries the WORST use of super and EX Super spamming possible, moreso than Zenka. In fact, he will often combine them in a normal combo or interrupt them in the worst timing possible, but that's not to mention Alpha can interrupt during your combo into his supers. Said supers are like taking the full brunt of Zenka's supers (though Alpha's EX Super is far worse than Zenka's).
 * It Got Worse: the newest edition of the game now gives Alpha Gill's Resurrection super (full hit point restoration, unless interrupted), provided Alpha's POW bar allows him to use it if KO'ed for the round.
 * It's worse than Gill's Resurrection. With Gill, you could just stand in front of his body and jab repeatedly to interrupt it and easily leave him at 25% health. But Team FK apparently took notes and made it so Alpha's Resurrection pushes the player away to keep that from happening, making it harder to hit him quickly.
 * Nightmare Cat, from Azumanga Fighter (a doujin Fighting Game based on Azumanga Daioh), is a permanently Burst Moded version of Kamineko. Now bear in mind that Burst Mode normally has to be triggered manually by filling all 5 bars of the special gauge, AND being at low health, but that gains access to that specific character's ultimate move, and having infinite uses of the super moves. Kamineko is one of the more annoying (but balanced) characters due to its height (it's a cat, as opposed to the rest of high school aged cast), however Nightmare Cat fires off super moves rapid fire, and uses its short height to it's advantage, ensuring you can barely land a hit. Fortunately, win or lose you progress to the next battle anyway.
 * The flash game South Park: Tokugawa has a final boss that is essentially, if not completely unbeatable, though this is in part due to poor game design in general, all of the unblockable moves and teleporting don't help.
 * Shizuru in Mai-HiME: Fuuka Taisen, when fought in Natsuki's Story mode. Shizuru loves to use her Super Special summon less than ten seconds into every battle, which fills the ground with slowly-advancing Kiyohime snake heads that are very hard to block, and will keep going indefinitely until they reach the edge of the screen. In addition, her "evil mode" lacks a block animation, which makes it complete guesswork to determine whether or not your hits connect, and has no problem spamming her whirling spear attack up close or whenever projectiles come her way. So, in essence, she's almost like her anime incarnation..
 * Natsuki may be better since she has ranged attacks. Consider Haruka the headbutt-main fighter...
 * MUGEN, the fighting Game Maker, obviously has several hundred of these. It's a good place to find most of the other entries on this list. There's also an entire cottage industry devoted to producing overpowered, nigh-invulnerable characters, many seemingly written for the express purpose of beating someone else's overpowered, nigh-invulnerable character. This makes for an SNK Boss Arms Race of sorts. Some of the most noteworthy examples include:
 * Hyper Gogeta by Supermystery, with his screen-filling Kamehameha.
 * The Legendary SSJ 3 Nightmare, probably one of the more infamous examples. Broly has a minute long intro of him powering up that knocks the opponent down and into a wall. If you've managed to survive that you have to deal with an annoyingly sturdy shield, shitloads of ki blasts and noisy shouting. And when he wants to, he can go straight to SSJ 4 where he becomes literally invincible and coats the screen with explosions.
 * Master Geese by Cannon Musume, an MVC-styled version of Geese Howard that has been nicknamed "Master Cheese" for his unblockable and cheap super moves. Not to mention his Deadly Rave is a One Hit Kill.
 * Hyper Neo-Kamek by Kamek, who gives a new definition to the phrase Beam Spam.
 * Light Yagami from Death Note who, well, has a Death Note. (and CAN READ HIS OPPONENT'S NAME FROM THE TOP OF THE SCREEN)
 * Mitigated slightly by his low defense. Doesn't excuse him from this trope, though.
 * Dark Reiko Hikari by Kamek, a crazy, blisteringly fast teenage girl who also hits you with a bus, and has TWO One Hit Kill moves. Voiced by Flonne.
 * The Rox Howard Clones, who turn a one on one into a one on seven.
 * Just about any 'Evil Ken' type (a wide variety of Ryus, Kens, Akumas, and Dans which began, apparently, with a certain build of Ken), who all try and outdo each other with ridiculous priority moves, combo capacity, and overpowered super moves.
 * Combine this with a lot of impressive chemicals and crank it Up to Eleven, and you have Rare Akuma.
 * Hyper Akuma also deserves a mention. To break it down completely, he has:
 * Ability to almost completely ignore attacks from other characters.
 * Ability to gain energy from being hit.
 * Insane attack speed. Racking up combos into the double digits is common when he is in play.
 * Very high strength. With the right moves he can wipe out an opponent within 10 seconds.
 * High movement speed. Capable of traversing the screen very quickly in a single leap.
 * A move which lets him cross the screen within 1 second and usually ends up behind the opponent. Also, he cannot be hit when using this move.
 * Another move which lets him cross the screen quickly. When he passes his opponent, it counts as a 7-hit combo. Spammable.
 * Projectile attacks which act as 8-hit combos. Also spammable, especially in air.
 * A healing factor that would put Wolverine and Deadpool to shame. Heals through super attacks.
 * Supers which often cover the screen, cannot be interrupted, have combo numbers ranging from 20-999, and eat up at least a third of the opponent's health bar. In addition, some of the Supers cost very little energy and some even recharge your energy bar.
 * Ability to SPAM super moves by mashing buttons at the right time while a super move is being performed.
 * And to top it all off, an aura which can reduce the opponent's health bar to nothing in seconds. Hyper Akuma has this on BY DEFAULT.
 * Neo-Reaper Isabeau SSJ 9, for an unblockable near-insta-kill fire attack.
 * Sephiroth, whose melee attacks cover half the screen, has 200% health as well as 220% defense, has three instant-kill moves (two of which are unblockable and unavoidable), can teleport with invulnerability, as well as charging his super energy invincibly, and is un-comboable. I've beaten him with Michael Jackson.
 * Though... said Sephiroth is considered an awful character since it features stolen codes and terrible collision boxes. And it's relatively easy to beat, specially if you use moves that drive him into custom states, like grapples.
 * There's also a Mega Man sprite edit of Sephiroth floating around that INSTANTLY KILLS YOU when his life meter drops to a certain point...great.
 * And while we're at it, there's Gustav Munchausen from the K.O.F. Memorial game, who features insane chip damage, full-screen supers, and a brutal AI, and gains super energy ultra-fast. Most critically, unlike most SNK bosses which reverse your moves with one hard-hitting move, Gustav opts to execute a 15-hit melee combo that fills his super bar, then uses one of his energy pillar supers for half your health!
 * The midboss Psyqhical is widely considered to be even more broken than Gustav himself. He possesses all of Gustav's traits, but also has full-screen specials, abuses counter moves that do ridiculous damage, can slow time down, and even trap you in a cube to take out 80% of your health. To top things off, the rest of his moveset is basically Beam Spam.
 * Someone thought it would be a brilliant idea to fuse the above two bosses, producing the edit known as Gustav M Type-F. He has a combination of both bosses' moves, and those belonging to Gustav have improved juggle qualities. But what makes him stand out is his infinitely chainable, lightning quick, invincible teleport which can be canceled from and into anything - a counter, a throw, even his highly damaging grab super! Worst of all, his AI really knows how to juggle and knows an infinite with his anti air strings move and his energy pillar supers, and it will happily abuse it!
 * The second K.O.F Memorial game brings us Element. Element moves at absurd speed, possesses several annoying grabs and slashes that take off large sections of your healthbar, spams a variety of multi-hit infinite priority projectiles, can summon explosions UNDER YOUR FEET and best of all, has White's instant-kill desperation move, complete with fake KO message!
 * In addition, Element is less a unique character than a class of extremely broken Iori edits. Since he was introduced at the ending of the first K.O.F Memorial game, people started speculating about him and making their own versions. This class of bosses has very flashy super moves that tend to revolve around elemental attacks, and when they get a hit on you, they will empty their extended super bar on you for an instant kill.
 * A Japanese imageboard took it upon themselves to make a Mugen game starring practically all their memes; as you may have guessed, insanity ensues. Still, nothing can prepare you for the final boss, Hato Sabure. To start, it's what appears to be a giant chocolate peep with Glowing Eyes of Doom. Who can fly via a jet engine and drop on you For Massive Damage, randomly counter physical blows by knocking you to the other side of the room, and is an absolute master of projectile spam-it has eye lasers, bombs, missiles, and fireballs, which all fire out of mechanical hatches that appear from its body. Fortunately, as with the rest of these bosses, the wide variety of characters allows a huge amount of ways of beating him to death.
 * Gold Ayu Tsukimiya. She's a little angel girl. The first fight with her is like fighting a tough (but not horrible) AI opponent. Take her out once though... and she gains a massively fast regenerating super bar, regenerating health, and I-no's infamous Megalomania attack.
 * Cheap Boss Type, is a parody of these. You think fans would know better than to complain about it given the name. Also brings up the question of why M.U.G.E.N. players simply don't delete crap characters and move on to better ones.
 * Zeeky H. Bomb, if only due to the fact that all his moves are strikers bar two. The saving grace of this fight is that Zeeky has no custom AI, and as such will constantly move randomly back and forth, leaving himself open.
 * Don Drago has made Geese, Yashiro, Takuma and Goenitz, and has a habit of including all their movelists into seperate modes. Do the maths.
 * Omega. He's a fair and very well-done example compared to the rest, sure, but the thing is, in the original games he appeared in, you can run away and take advantage of his Ax Crazy fighting style. This time, you can't. And he has new supers. Oh Crap.
 * And then there was "Mecha Scorpio". Even the author is now ashamed of it! Here's all the things wrong with it-
 * Short, making it hard to hit with high attacks.
 * Huge damage with its infinite priority claws, tail, fire and earth based attacks, as well as fast power gain from just using them.
 * It could poison the opponent for the round every time it hit with its stinger tail, causing them to flinch and take damage every few seconds (the poison effect was stackable too!). Worst of all, the poison never went away!
 * Countered all grabs with a powerful move, not only did it take off a quarter of the opponent's health, it also gave them the poison status too.
 * A One Hit Kill that it WILL use if it got up to max power, and it could only be avoided by crouching and blocking. If the opponent didn't do so, they would be sucked up by a sandstorm, dropped into the middle of a desert, crushed with four rock pillars, then blown up.
 * Finally, if most of the above-mentioned Game Breakers were used against it, it would turn invincible and all its attacks would become One Hit Kills!
 * Chuck Norris. If anything, the internet rumours understated his power.
 * He's way beyond SNK Boss. At least the player has a small chance to defeat an SNK Boss... as for fighting against Chuck Norris, no such luck - The Heart Attack Button doesn't even work on him! If you didn't think to place Norris outside the normal fighting order, the jig is up when you run into him.
 * Most Touhou Project characters can become this if their movesets are ported directly. The original fighting games are built around Bullet Hell as opposed to melee and movesets are balanced accordingly, giving each character massive barrages and means to counter the same. Contrast this with the average fighting game character who is almost melee exclusive.
 * Finally, speaking of edit characters, many of the above mentioned SNK bosses have been ported into MUGEN. Some authors will port them exactly as they were in the original game. However, many authors will edit them to tack on new supers and special moves, making them an even worse pain in the rear to fight. Using the King of Fighters Memorial edits as examples:
 * Goenitz gets a couple of screen filler supers where he fills the screen with tornados and a version of Yonokaze that travels towards his opponent and combos them for 8 hits.
 * Orochi receives several Marukare variants, solely for the purpose of being cancelled into each other to obliterate his opponent's lifebar. He also summons a wave of energy pillars as a special
 * Krizalid gets a Megaton Punch super that does serious damage, souped-up versions of Desperate Overdrive, a super grab and a MAX move where he fills the screen with explosions.
 * Original Zero and Clone Zero have their movesets combined, allowing the former to use both his strikers and Clone Zero's Shadow Arts. As with Orochi, he receives a couple of variants to his Black Hole.
 * Igniz gets a full screen version of Chaos Tide (the quad-energy blast), a screen filler, Krizalid's End of Heaven super, the Zeroes' Black Hole and a super where he charges up a large energy ball that is an instant kill if not blocked.
 * In the first renditions of Melty Blood, we had Aoko Aozaki. She was pretty much a Fighting Game version of a Touhou character, Beam Spam included. She was later balanced as a normal character and given a new moveset. There was also the secret boss Giant Akiha, who was a parody of Apocalypse, who did an insane amount of damage. A later revision replaced G-Akiha with Neko-Arc, a small, deformed cat version of Arcueid which had attacks with absolute priority. Also, she was small and very hard to hit.
 * Act Cadenza introduced White Len, an alternate version of Len that easily takes Aoko's former place as the SNK Boss. She had a drastically different moveset than in the Ver. B update, and most of her attacks had absolute priority and did a lot of damage. Neko-Arc also got an alternate version called Neko-Arc Chaos, who parodied Nrvqnsr Chaos' moveset but with the same attributes as the original Neko-Arc.
 * Ver. B of Act Cadenza introduced a new hidden boss: Neko-Chaos Black G666. Created by Kohaku in an alternate story mode for Neko-Arc, this is a true successor to G-Akiha who loves to abuse Beam Spam, but also has other attacks like a drill and a missile arm. It's extremely hard to beat due to the large amount of damage it does. At first it can only be fought in Neko-Arc Chaos' secret story, but if you beat it you unlock Giant Attack Mode, which lets you beat it with any character. The catch with Neko? He's pretty susceptible to multiple-hit attacks after he attacks, so you can pretty much punish his moves with a combo or two.
 * Actress Again gives us Dust of Osiris, only available to certain characters. It's an alternate-reality version of Sion, and it's pretty cheap in its own right. Look it up on YouTube and see for yourself.
 * And then Current Code made her even worse: She now has an Arc Drive, which makes her invincible for a few seconds, after which, she nukes the entire screen with an unblockable attack. It is possible to dodge/shield it, but you need a good timing.
 * Also in Actress Again, if you beat Boss Rush mode without losing a round, well... you get to fight Archetype Arcueid, who can kill you instantly. And is then unlocked as a playable character... with all her moves and damage intact.
 * Touhou Project (fortunately the Touhou fighting games avert this trope in multiplayer by keeping story mode spellcards separate from multiplayer):
 * Immaterial and Missing Power has preliminary boss Yukari Yakumo and her Infinite Speed Flying Object, and Final Boss Suika Ibuki's Pandemonium.
 * Everybody is a more dangerous opponent in Story Mode (where these two are bosses); the gameplay consists of bouts of normal combat with your adversary interspersed between trying to dodge one of her souped-up, perpetual-use spell cards while getting enough attacks through to knock her out of the casting trance. They also get more life and some armoring. Yukari and Suika simply take this well beyond any of the regular Story Mode characters.
 * Tenshi Hinanai of Scarlet Weather Rhapsody eventually fits this trope. While at first she's only a little stronger than most of the enemies you've fought so far, her final attack is absolutely brutal. If you don't knock her out before she starts doing it, she starts spamming almost impossible to dodge lasers. Oh, and if you get hit by one, she starts another one before the first one finishes, so if you ever get hit by one of these lasers, there's a very good chance that you'll just die.
 * In Lunatic mode, she fires 3 at once which actually is quite unfair. However due to the limit system it will only do about 3k damage, which is still a lot but not enough to kill you. The gimmick to this spell is to bait her lasers on 1 side then graze though them. Also, this attack will guard break near instantly; if you accidentally started blocking, border escape immediately.
 * Yukari Yakumo is also a brutal example (again). Her very first spellcard may not look like much but the projectiles move in a specific pattern that makes it impossible to counterattack. If you're hit once, the next projectile will get you the precise moment you recover, leaving no time to block. If you attack after a successful dodge, you will have no time to block, and once you're hit before your attack connects, it's negated.
 * Act Cadenza Strife, a fanmade Tales Series fighting game, has several boss characters such as Dhaos, Synch and Nebilim, Hugo and Barbatos, and Shizel. All of them have at least one ridiculous gimmick that makes beating them a pain (for example, at low HP Barbatos will use a completely unstoppable move that instantly kills you no matter what), but in general it's not too hard unless you're doing a boss rush. However, that's because those guys are all playable (though the CPU versions have benefits the playable versions do not, such as the aforementioned instant kill move). However, the game also has several unplayable completely ridiculous secret bosses that fulfill this trope.
 * First off is Yggdrassil. His main attack, Yggdrassil Laser, hits everything in front of him for a ridiculous amount of damage, makes him invincible during the entire animation (including when he starts it), and is often spammed. He also has two uninterruptable and unblockable moves that he can bust out if you get too close. His other attacks are almost all spells, which normally require a casting time of some sort. Yggdrassil instant casts them. Did I mention that his version of Photon counts as a grab, so it can't be blocked? And that it can hit you no matter where you are on the field? Even worse, his Limit Break can be used for a piddling amount of TP, does massive damage (about a third of the average lifebar), and the only way to avoid it depends entirely on your luck? And as a final Screw You, at low HP Yggdrassil uses a completely unstoppable attack that hits the entire screen for a decent amount of damage, which will probably kill you.
 * Next is Nereid. She(?) has a ridiculous amount of immunity frames, namely every time she casts a spell. Oh, and almost her entire movelist is spells. Spells that she will spam like crazy, usually causing the player to literally have to wait until her AI makes her use a spell that doesn't leave you completely helpless for ten seconds. Aside from that, she is fond of casting a spell that causes rocks to shoot out of the ground in front of and behind her. These rocks can not be blocked, and during the entire animation Nereid is completely invincible. And that's not even counting her Limit Break, which does a large chunk of damage and has a tendency to break your guard with the initial (weak) hits, allowing the final (strong) hit to rip into your HP. Finally, she also has a low HP desperation attack that hits the entire screen. Unlike Yggdrassil, though, Reid Hershel, the main character of Tales of Eternia, can counter her desperation move with an attack that instantly kills her as a reference to Tales of Eternia.
 * And last, but not least, is the living incarnation of bullshit: Alexei. This asshole spams spells that hit the entire field, such as the infamous Tidal Wave. But unlike Yggdrassil and Nereid, he's actually open for attack while casting. Or he would be, but because he's an asshole his spell guard (basically, whenever you cast a spell in ACS, your character will not flinch for a certain number of hits. This allows a caster to actually cast a spell, but also means that melee attackers can interrupt the spell if they reach the caster fast enough) is miles above other characters, with the end result being that even if you attack him for the entire period of his spell casting you can't stop the spell. But when he's not casting, Alexei is usually doing one of three things. Either he's attacking you with his ridiculously long range melee moves, using his Limit Break, which is just as absurd as it was in Tales of Vesperia, or going into Overlimit 2 so he can kill you faster.
 * One of Ougon Musoukyoku's expansions has one of these after beating Arcade on Hard difficulty without losing a single round. In it, you get a Final Battle "to end the game", where you have to fight against two Black Battlers in the same team.

As if the difficulty level isn't enough, he also gains life from damage dealt (which is usually a 100% heal), recovers life over time, takes little damage, does gigantic damage, crushes defense within a few hits, has infinite Special Meter and auto guard (can block while attacking or even while taking damage).

And while you need to change your character using a usually risky and highly-punishable move to activate one of your two special abilities for a short period of time, Black Battler has eight of those special abilities ALWAYS active.