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 (with priority over ALL OTHER FIREBALLS), 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.
To wit: Ivan Ooze can do his invincible DP out of hitstun. You HIT him — and he hits you right back.
Lord Zedd, who you fight before Ooze, could simply teleport whenever he wanted, even when he's blocking or being hit, meaning combos and hypers were useless against him.
Alpha-152 in Dead or Alive 4, a superpowered Kasumi clone made of... something (Jello? Cool Mint Listerine? Just plain energy?). She's unplayable and has a unique move set including combos (both combo melee attacks and combo grabs/throws) 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.
Certain characters have an easier time fighting her than others. Quicker characters and characters that are difficult to read (Helena, Brad) 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.
The worst part about her, not yet mentioned, is her abuse of attack range and Perfect-Play A.I.. She stays just out of range of your (standard) attacks. When you try to hit her and your attack falls short, she'll nail you for the aforementioned 2/3 of your health while you're in cooldown. If you (try to) run in and attack, she'll either nail you before you get to the "attack" part, or teleport away. If you sit in defense, she'll move forward in a split second and hit you with a similarly overpowered grab combo before you have a chance to hit her.
This makes the best way to beat her a (partial; she's still not stupid) A.I. Breaker - attacks she doesn't think can hit her at the current range, but actually can. Typically, attacks involving some form of lunge. Strafing sideways before running in can also trip up her ranging avoidance.
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, meaning he's the only character in the game with a ranged attack.
Tengu was actually really easy to beat if you learned his weakness: the wind-gust manoeuvre 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 Re-release, 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 supreme Mugen Tenshin clan badass and father of basically every ninja in the game, Shiden, who pulls so many moves out of his ass it's sheer baffling. 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, the penultimate boss Sakaki, who 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 Katze, who has a revolver, while the player has only a melee weapon. Katze 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 willJust Shoot You.
Comparatively, the other gun-wielding character in the second game, Tsubame, totes an M-16; resulting in a much slower fight for you and her as you try to make her reload.
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 drillchainsaw 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 (Although, you know... it's overjumpable, thankfully) super where she shoots a raygun at you and turns you into a FROG. ...oh, and she's almostunhittable 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 KOed. 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 does a ton of damage and can chip you away if you block it. And he buttonreads. Welcome to hell.
Super Smash Bros.. Melee, Giga Bowser was designed to be one; his attacks have far greater reach and much larger hitboxes than what any other character could throw out while hitting even harder than Ganondorf's attacks, he's completely immune to all grabs (including special grabs), his shield can not break (which makes his immunity to grabs even more broken), his recovery move covers great distance while having extremely large hitboxes and significant amounts of invincibility that makes it near impossible to edgeguard him (on top of him being far heavier than the playable cast to make killing him even more difficult), and many of his moves have effects to significantly improve their effectiveness (such as his massive Fire Breath that doesn't shrink in size, and his Whirling Fortress that attacks with the aforementioned abnormally large hitboxes and invincibility). However, Giga Bowser ends up not being an SNK boss when you actually fight him, as Melee's notoriously poor and easily exploited AI turns Giga Bowser into a bumbling giant punching bag that barely utilises any of Giga Bowser's tremendously powerful abilities, rather than being the terrifyingly broken character he would be in the hands of a competent player.
Super Smash Bros. For 3DS/Wii U introduces a legitimate example through Master Core, Master Hand's terrifying One-Winged Angel. The battle consists of 4 different forms, all with their own set of fast, overwhelming attacks (not counting a "joke" fifth form that can kill you in one hit). And in the Wii U version, it gets an additional form. Thankfully, you only get to fight it by playing on higher difficulties.
The eponymous Eternal Champion from the Genesis fighter game 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.
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 merges the two worlds, resulting in the implied deaths of millions. 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 goes off five seconds after it hits you, suddenly dealing insane damage and putiting 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.
One other thing. Unlike in Other Score attacks by arc System works, you have unlimited continues and with each try, Parace's health goes down with each one little by little. However, considering the above, You. Will. Need. Them! And the lower her health is, the more agressive she gets. Basically it's as if the development team knew how hard she would be and did that to try and compensate. If the score attack acted like other games, Parace would more then likely be downright unbeatable!
As of LOVE MAX!!!, Parace's starting health no longer decreases when you continue. Good Luck. It's somewhat justified by the fact that she's no longer the last opponent in Score Attack, but fought in a special Trial Mode instead.
Also in LOVE MAX!!!!!!, there's Fiona, the final boss of the newly-added Time Attack mode. She's constantly going in Extend mode and has a full super meter. So expect her to spam her Arcana Blaze and try to use her Extended Critical Heart on you. The worst part? HER ARCANA IS MILDRED. And expect her to spam Mildred's Extend Force on you every now and then. Not only that, but Mildred will attack with her normals and supers. Especially the one where she traps you in a bubble and swords come out to attack. It's basically a next-gen version of the Cammy Vs. Juli and Juni fight from Street Fighter Alpha 3.
There's also the newly-added Survival Score Attack, where you fight high-level AI versions of every character in the game. The final boss is Kamui, who has a full super meter and is in PERMANENT Extend mode. The worst part? She makes Fiona look like a JOKE. She powers up with her Arcana, Anutpada, at the beginning of the match. And as a result, she becomes MUCH FASTER, can phase through attacks, and gains a new super where she traps you and can slash you as many times as she pleases. It's extremely hard to combo her. Her A.I. can also read your inputs.
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 Jester from Ballz 3D: teleporting, attacks from a long range, various tripping moves, and he resurrects himself when you knock him out once.
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 A.I. 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 bodyguard that shot him in the back of the head with an arrow.
Warriors Orochi series seems to make Lu Bu's A.I. 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 Red Shirts 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.
In Dynasty Warriors Online, every Musou general, the playable characters from the Dynasty Warriors games rather than a custom character, are SNK Bosses for their unique bonuses, which are all achievable by players but not all at once. They are horribly dumb, and don't really pose a threat by simply being on the map, making it much calmer when they are around, but when you face one it's hell. Every single general has at least three advantages: 1) they all have at minimum hyper armor, meaning they only flinch at Limit Breaks, and some have stronger, like Lu Bu, that means they don't flinch at even that; 2) their stats are through the roof, they cause massive damage and can take attacks great, making them really lethal to be around, as they don't flinch easily it's hard to keep them from attacking and they are damage sponges; and 3) they have flunkies that are not as powerful as them but still have the same resistance and rather upgraded stats for a mook. After all of that, they are hard to defeat, but they do have weaknesses, such as not having any special resistance to elements allowing them to be forcibly stunned or pushed. They can also be distracted easily, and you can get them off you by running into a crowd of either your own or bandit (hostile to both sides) mooks.
The prototype of all 2D 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.
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. And as if THAT weren't bad enough, if you wind up dying, your teammates just give up fighting, even if they're still healthy enough to continue!
"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).
Any enemy with illegal parts can count as this to varying degrees. In-universe, illegal parts are illegal because they apparently put too much of a strain on the user's mind. Gameplay-wise, though, they're illegal because they're purposefully broken and unbalanced (naturally, every part used by Rahu's different stages are all illegal parts.)
Chaos from Dissidia: Final Fantasy is a great example of this trope. He attacks faster than 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 A.I. 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.
Another way to make his Inward Chaos form disappointingly easy is to use Exdeath. Chaos's A.I. is so aggressive that if you pull off an attack right at the start of the match, he'll counter with his own longer-ranged attack that probably overrides yours. Usually, this is bad; however, it's funny to see him try this with Exdeath's Delta Attack, which forms a large barrier in front of Exdeath that blocks incoming attacks and staggers the enemy before striking them with a short beam for damage. This attack's beam is usually slow, unless it blocks and staggers with the barrier, in which case it'll fire off the beam a second later for a guaranteed hit. Equip Exdeath with every item you can that will get his starting Bravery to 9999, and just use Delta Attack for each of the three rounds. Is Chaos really stupid enough to always instantly swipe into your staggering defensive barrier and get ravaged by a max-power Delta Attack, meaning you can beat him simply by pressing one button each round for three one-hit-K.O. victories? Spoiler: Yes. A thousand times, yes. You will spend more time in the loading and victory screens than you will actually fighting Chaos.
The second game features Feral Chaos 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, and 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 it out is impossible. His HP attacks drain your EX Gauge to emptiness, so using it is difficult. The real kicker comes after you finally manage to beat him: the first fight was just a manikin and 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, the playable version 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).
Forget M.U.G.E.N, this guy is basically the hardest boss throughout all fighting games since its release. Observe. For further proof? Even the writers from game magazines gave up on writing strategies against him.
Later it was discovered that he has an A.I. flaw — simply going for lows, especially using Wulong, could do the job to defeat the General. This video shows Mikado's successful attempt (in 2014), though by the narrowest of margins, to finally defeat the self-proclaimed PERFECT SOLDIER.
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 YuYu 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.
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.
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?!"
Most boss battles on Battle Of Z are 4-on-1 fights where the boss is alone. However, the game gives quite a few advantages to the boss, such as a 1000% boost on their HP, massive boosts on all his stats (wich makes them even sturdier while making their moves strong enough to down you in seconds), and the ability to simply disappear and appear in the other side of the map. The main problem are the two other bonuses: infinite Energy and Super Armor. Not only bosses can throw in their super moves at will (wich will deal massive damage and they are completely invincible while doing so), as they can break out of your attacks and start a combo on you. They can also tech recover from anything, meaning that if the boss wants, he can break out of pretty much anything you might be doing. against it.
Dragon Ball Xenoverse: the Super Sayian bosses, compared to SSJ used by the player (including using actually those characters). Normally, SSJ transformaton allows you to use supers and ultimates for free while draining your Ki bar by itself, while if you play a "permanent" SSJ version of the character it is purely cosmetical and you need to activate a higher stage to get the benefit - however bosses with those forms permanently on do not have it run out and can use skills with impunity. The worst case in Parallel Quest pitting you against the whole Son family - if you linger in one spot for even a moment after entering the zone, you will be instantly beam spammed to death.
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!
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.
And then Storm 3 tops them all with the Reanimated Second Mizukage. Yes, Trollkage is the game's SNK Boss, and his nickname has never been more fitting than in this game. Unlike the other characters above, he's an explicitly unplayable boss character, so the devs didn't even need to balance him. He basically takes all the annoyance of Deidera and Itachi, combines them, and somehow manages to makes them WORSE! He loves to spam streams of long-ranged water projectiles that go on far longer than any other ranged barrage (to the point where trying to block the the whole thing will break your guard). Think you could stop that by getting close to him? Think again. He has an exploding Water Clone jutsu that works a lot like Itachi's (basically a moving barrier that explodes if you touch it), only it gets bigger the further it goes, and it can chase you the entire length of the arena. And he also has a second clone attack that's easier to dodge, but much faster. The one saving grace the game gives you is that he does not appear to have an Ultimate. To top it all off, you have to fight him in essentially the middle of a Boss Rush with the other revived Kages, who are only marginally weaker than him. And after that you face (with no oppertunity to save)...
The real Madara Uchiha, who has near Perfect-Play A.I. and some devastating attacks. Then again, this guy is practically an SNK Boss in-canon, so it's justified in his case. In fact, he's actually LESS of an SNK Boss in the game compared to in-canon, considering this version lacks multiple massive meteor drop, instant knock-out plant pollen, and other moves.
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 two playable characters have projectiles... but only ONE can use it infinitely, 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 The King of Fighters '99-2003? Not surprised?
Rouge from Ranma ½: Battle Renaissance on PS1: 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 DoDonPachi - 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 GameCardinal 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 making a nearly impossible boss to beat with most characters (except Peacock fittingly enough) in the Pre-Patch version of the game. Even after the patch, however, which adds hitstun, and more visibility to her attacks, she remains a difficult boss to defeat.
This is made even worse with Marie 300% in Encore, as she has triple her starting health, and is locked to Nightmare Difficulty.
In Fukua's story mode, the final opponent is Filia, the character Fukua is cloned from. Filia has at least twice (possibly three times) the health you have for this fight (and this fight alone, of course), is locked to Nightmare difficulty even if you started the Story Mode on Easy and starts the match with five bars of Dramatic Tension (the game's super meter) while you start with the usual one. And the timer on this fight does not decrease but stays at 99 throughout, meaning you have to win outright. Then of course there's the minor issue that Filia is also one of the best characters in the game even normally and regularly tops the tier lists.
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.
Metal Sonic is made slightly easier when you realize that most of those attacks are very noticeably telegraphed and can be sidestepped, but you still need to be at a fair distance in order to sidestep far enough to not get hit. It's still not very much help against his throw move and he STILL has a chestbeam that only has a split second of warning before execution... that is, YOUR execution because you'll be dead.
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 Artificial 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.
In an interesting subversion, Sonic Battle lets you create your ownSNK Boss in the form of Emerl. A couple of character battles pit you (as Sonic/Shadow/Cream/etc.) against the little fighting robot equipped with all of the best skills (or you can reset his skills back to his default attacks for a pitifully easy fight). However, it's played straight during the final story, where you, as Sonic, must take down Emerl with ALL of his Ultimate Skills equipped.
Chaos would be this as well thanks to his scary good reach, good defense, and very strong attacks. Only problem? He's too... damn... slow.
In the SD Hiryu mode from the N64 RPG/Fighter hybrid known as Flying Dragon, there's a boss known as Shin Ryumaou. Not only is his moveset cheap (featuring a speedy fireball move and a triple jump kick that almost always counters your combos), he's also equipped with a rare item that can hit you no matter where you are, is unblockable, and absorbs your HP. It doesn't stop there, because he also has three forms, and his second form is the worst. In his second form, he cannot be stunned half the time, none of your combos work on him, and above all, he revives nine times. Granted, the amount of HP restored decreases after his first revival, but this guy is an unbelievable hassle.
Felden, from Galaxy Fight, was totally unbeatable. All his attacks had absolute priority and he could hit you from a character's lenght, while taking good chunks of healt.
Makaitaitei Fernandez/Fernandeath from Waku Waku 7. While he was a big target, he could hit you from a distance with all his attacks and they all hit hard.
While all other characters had to charge their Hara Hara (unblockable max level super) attacks, Fernandez's Hara Hara comes out instantly, and he will use it whenever he feels like it.
In Battle Assault 3: Featuring Gundam Seed, we have the Final Boss, Rau Le Creuset and his Providence Gundam. Now you fight him on the stage before, but you had an ally backing you up and it was just him with no time limit. This time however, you have no ally, there are about 4 of the strongest enemies preceding him and you have a time limit of around 2 and a half minutes. Oh and just like the many examples above if you time out against him, even if you have more health than him, you lose because the GENESIS fires, destroying the Earth. And even though he himself isn't SNK boss material, albeit he does love to use Beam Spam with his funnels and frequently uses his more powerful attacks, the fact that by the time you kill the previous enemies you're already scrambling for time and likely to make mistakes fighting him, causing him to kill you easier.
The previous Gundam Battle Master/Battle Assault games were no different.
The first, Japan-exclusive title, The Battle Master had Big Zam, Neue Ziel, and Psyco Gundam Mk. III. Big Zam and Neue Ziel were giant, and had a large laser, but were otherwise no problem. Psyco Mk. III, however, had large range for most of its attacks, including its Beam Saber and a full body beam attack. It also had an uppercut that could take out half of one of your three health bars.
In the first released to the US, Battle Master 2/Battle Assault, all these bosses returned, and Psyco was made even harder. Though it lost its full-body beam, it still had its uppercut and Beam Saber, which, due to the way sabers work in this game, was now unblockable. And if you dodged it, you still took some damage due to the way the dodge system works in this game; don't dodge it and you took even more.
And when you beat Psyco, you entered a match with the Hydra Gundam. This one had a laser attack that didn't use up energy unlike all the other lasers in the game, homed in on your position, and fired twice in a row. It also had a Beam Saber attack which came out immediately, while all other Beam Saber attacks had a delay to offset their unblockable nature. For its super move, it had a combo attack that ended in a saber slice, meaning you had to dodge the last hit.
Battle Assault 2, the US exclusive, had all the previous bosses with no changes, plus two new ones from the Non-UC series included.
Gundam Epyon was a melee only suit, which means a lot of unblockable attacks, including its super move.
But the grand champion in the series is the Devil/Dark Gundam, which not only was giant like the Psyco, had attacks with a large amount of range, including an unblockable, full length laser attack.
Divekick features S-Kill as the final boss of story mode. He is playable normally, but the boss version has permanent Kick Factor, granting him infinite access to his Trick and Parry special moves. Trick instantly teleports him to the most optimal angle where his kick can reach you, while Parry allows him to block your attack and get a guaranteed Headshot, which dizzies you in the next round. Fortunately, his Kick Factor is temporarily disabled with a headshot just like everyone else's.
In the Nintendo DS version of the game the final boss of every mode is Xaviax. He is constantly protected by a shield that reduces the damage of all of your attacks by over 50% and prevents him from flinching when you attack him and he has 3 super moves where he fires giant lasers at you that are nearly impossible to dodge. His third and most powerful laser attack WILL kill you in one hit. He fires five lasers; the first knocks you down- the other four hit you while you're down and helpless. Fortunately Xaviax can be unlocked for use without any decrease in power when you use him.
The Wii version of the game will almost always have a fight against a Rider who is always in Guard Vent mode near the end of the Mirror World mode- the Rider in question will almost always be Strike or Sting; sometimes Thrust. Enemies in Guard Vent mode take half the damage from your attacks and never flinch when hit by your attacks. If you throw a punch, they will throw a punch without stopping and before you can react. Summoning your Advent Beast or using a Strike Vent card (if your character has one) can cause an enemy to flinch while in Guard Vent mode, but doing both requires using a lot of your special gauge and the latter can only be done once per fight.
The Undertaker, from the "Defeat the Streak" mode of WWE 2K14 definitely qualifies. The match starts out normal, but the more damage you hit him with, the more powerfulhe becomes. Examples of this are the lights going out, 'Taker Teleporting after being hit with a finisher, countering pins into a chokeslam (as Retro 'Taker) or the Hell's Gate submission hold (as Modern 'Taker) and losing all damage inflicted to him. Fighting him with Batista, Shawn Michaels or even Diesel is difficult as it is; trying to take him down with King Kong Bundy is damn near impossible.
Retro Undertaker is slightly less SNK Boss-like than modern-day Undertaker — he only counters pins into a chokeslam (as mentioned above) and can, in fact, be beaten in less than 10 minutes — but the current Undertaker is damn near impossible. Oh, and both 'Takers can easily hit you with a finisher REGARDLESS OF WHETHER OR NOT YOU HIT R2 TO COUNTER a microsecond after picking you up off the mat. Oh, and he's also just a smidge faster than Modern 'Taker, so it's truly a case of Pick Your Poison—-especially if you intend to unlock all the WrestleMania photos by beating him with Triple H, Edge, CM Punk, Big Show or King Kong Bundy.
Oh, and for those of you thinking you can just beat Retro 'Taker instead of Modern 'Taker to earn the alternate attires you get for ending the streak? You HAVE to beat Modern 'Taker with either Diesel or King Kong Bundy to unlock Retro 'Taker. Yeah...have funwith that.
In Aquapazza, the final boss of Story Mode is Ma-ryan and a main character of her choice depending on who your main character is. In addition to her normal partner attacks, she has Super Move variants of those attacks that she can unleash at any time. Her partner is an emotionless shadow clone of one of the main characters and doesn't experience any fluctuations in strength during the match like your character does. Finally, if she winds up on the losing end of a beatdown that would otherwise decide the match and has 3 or more stocks of Super Meter, she can rewind time to recharge her main fighter's health to 50% to delay/deny your victory.
Then you face Chizuru in Another Story mode, who is by far the strongest Lightning Bruiser in the game. One of her special attacks even involves a textbook Speed Blitz. If you're not careful, she can combo and fling you all around the screen to your death in a matter of seconds. On top of that, her health and Super meter constantly charge throughout the battle.
Shadow Jago, the True Final Boss of Killer Instinct (2013) on Xbox One, added along with the Fulgore update. As a playable character, Shadow Jago is simply a different skin for Jago with a unique voice pack. However as a boss, he's a completely different beast, with different moves and move properties (as well as the only Ultimate Combo in the game to boot). To even get to him, you must first have all three of a character's endings unlocked then beat Arcade Mode on Medium whilst scoring as many Supreme and Ultra victories as possible. Get to him and get ready for a hell of a fight (even on Medium), as Shadow Jago's adaptive AI properties allow him to react swiftly to repetitive strategies. If not for his overpowered moveset, Shadow Jago might not even qualify (as he's hard because the computer plays him really well, which is another trope) but since his attacks are all buffed up he's still such.
Think Shadow Jago was hard enough? Enter Shadow Lord Gargos. The developers themselves have stated that they are purposefully designing him to be "the cheapest fighting game boss ever made". He has a 3rd Strike style Parry, he can summon both of his minions at once with just one summon, he constantly has the super armor from his Instinct Mode on without being in Instinct Mode, he regenerates every single one of his meters (health, Instinct, AND Shadow meter), and whenever he hits you his regeneration accelerates to absurd speeds. To top it all off, his AI is always set to Killer difficulty much like Shadow Jago, no matter what difficulty you have the game set to. Shadow Lord Gargos is so ridiculously broken that the developers had to allow you to weaken him in order to make the fight slightly more fair.
Dark Heart in the VR Troopers fighting game. One of his specials basically renders him invincible whenever he wants (not just invincible, but even touching him, melee attacks included, damages you.)
From Teenage Mutant Ninja Turtles: Tournament Fighters, the Final Boss of the Super NES version, Karai, is this. She's fast, hits hard and has many moves that are difficult to avoid. This video shows her in action while being used by a human player, and gives some idea of how overpowered she is; the only opponent that gives the player any significant trouble is Karai herself, when the player is trying to fight "fair".
The Genesis version is already hard on its own, but the one that takes the cake is not Karai (who's also in here), but the first sub-boss Triceraton. He's a Lightning Bruiser that is likely to close in and then start chewing on you as his throw, which would end with your character jumping backwards, which enables him to move forward, then throw you again. This would look normal, the Turtles Leonardo and Raphael also have this kind of throw. In case of Triceraton, however, due to Perfect-Play A.I. and this being his only throw, Triceraton WILL spam this move once he ever grabs you in his throw, until you die. Bottom line, if he ever grabs you for a throw, you've got about 90% chance of losing instantly.
Hilda Rize of Vanguard Princess is a projectile-heavy character in a game where most characters have few projectiles and are not really designed with countermeasures to them. In the Japanese version of the game, this is balanced by her AI being fairly easily confused, but in the English translation, it's combined with a Perfect-Play A.I. who can spam projectiles that take fireball-motions or other such tricks in human hands. She can force you into the corner and whittle down your health, and punish you severely whenever you try to get close.
Draglade, being a platformer/RPG/Rhythm/Fighting game hybrid, has always one boss that manages to provide a hardcore challenge to everyone except the most hardcore and diverse of players. Even so there are a few that stand out.
The 2 Gorilla Variants of either mission done in Oakland or Raiden are the 2 biggest cases of this. They have high HP and probably require at least 500 hits before being taken down. They have high attack, which means that you will usually die in 5 hits. To top it all of they have high speeds and can combo you easily since their huge sprite do not force them to travel a long distance. If you know that they also can defend themselves, have a fake defense move designed to lure players in an attack of theirs and a move that boosts their attack and damages the unfortunate player trying to attack him from the air you understand that they are monsters so huge that it is rare to find a player that beats them without level grinding a lot.
President D. Unlike other bosses he has 2 forms.
His first form is centered around massive speed. He can teleport around the ring and fire projectiles that have a huge hitting window or just simply attack you from behind. Later on in the battle he will also gain a move that creates 2 spirals of death, which if used in combo can do as much as 700 damage. The fact that he has 4500 HP also means that it will take a while to beat him.
In his second form only his floating head takes damage, which means that your ground-based rhythm combo is useless and that you can only really give him 75 damage points unless your spells can hit stuff in the air. His attacks are fast and cover almost the entire screen and he even spawns enemies that do knockback damage which will leave you standing still for long enough that the boss can spawn its own attacks on you, which again leaves you open for knockback damage by the enemies. To top it all of he has 6000 HP. What starts as a special kind of battle will quickly turn into a pinball party with the player character being the ball.
Fighting Masters has the resident Big Bad, Lord Valgasu: His lifebar is slightly longer than anyone else's (Even Xenon), he has long range with his normals and moves very fast, making it very probable that he grabs you; his grapple moves deal unforgiveable amounts of damage and, if you're unlucky enough, he'll grab you again without giving you any chance of escaping, effectively emptying your lifebar in a matter of seconds. Compared to him, the previous battles feel pretty easy. Fortunately, he suffers the same AI issue as the other characters, making him relatively easy to defeat if you know how to deal with him.
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/Mirror Mizuka/Eien no Mizuka, 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).
Alpha has two EX Supers, one of them doing about 75% damage and being unblockable, the other doing less damage (only 50%!,) but still being unblockable and the only true full-screen attack in the game, meaning you have to be either knocked down or in the middle of some kind of teleport move to avoid it.
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 its 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. Good thing her "good side" is an unlockable character.
Natsuki may be better since she has ranged attacks. Consider Haruka the headbutt-main fighter...
M.U.G.E.N, 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:
The Legendary SSJ3 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 SSJ4 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.
Mitigated slightly by his low defense. Doesn't excuse him from this trope, though.
Also leads to a couple of moments of rage, where he shouldn't be able to tell the name. For example, Fate/stay night has a character in Mugen called Archer, only his real name is Shirou Emiya, only that isn't his birth name, and is actually the name he was given after the grail fire of Fate/Zero wiped out a large portion of the city he lived in, with him as the only survivor who can't remember anything before the fire. Meaning Light can kill characters using an alias of an alias of a completely unknown name.
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.
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 SSJ9, 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.
What about the Toa Mata? Instead of being something like Pain from Naruto Ultimate Ninja Storm, each button is a different Toa attack. But Only Tahu is playable from the start, and pressing a button while the Bar is at halfway will summon a different one. This is not the end however:
You have to hit Tahu in order to damage them, and he is usually elbow deep in his spamming teammates.
So Many ultimate attacks, that you don't understand the meaning of cheap.
Each Toa has an ultimate, which is Telegraphed by a a white sheen, and usually takes chunks of health off of your bar.
Then using the TAUNT button, you cause them to do ALL their Supers, at once.The textbook defeinition of bad Sportsmanship.
Then there are fusion attacks, where two Toa do a new super attack, which again, takes chunks(Tahu and Lewa= Fire tornado, Hali and Pohatu, water stream= with a rock willing Onua and Kpaka= Ice shard blast, then a earthquake launching up MORE ice spheres.). And they [Take it up to Eleven] by going into a Kata form, where elemental fury is rife.
Though they need their supers to do most of the afromented, a palette allows they to have all six pre-summoned, and will a constantly full bar. You may soil your clothing now.
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 AyuTsukimiya. 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.
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 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. It is also almost impossible to see when he uses his counter moves!
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.
Sinobu returns, but several times as cheap; he uses lightning and wind element attacks simultaneously, has TWO 4-hit one frame projectiles and is very fast on foot. Most critically, remember those orbs that surrounded him in his official appearance? They're now a super that forces you to block, allowing Sinobu to back you into the corner and chip you to death!
Not even the relatively balanced midboss Kusanagi is immune. He's mostly the same... except that he now runs at 50 miles an hour for continuous mixup pressure. Have fun escaping the corner!
Kuuga, from Ruina and Azuma is an absolute BEAST, and God help you if you beat him in the first round. And woe betide you if he hits you with the Rider Kick—-anything below 60% health, and you're done. And he can do all of this in UNDER. TEN. SECONDS. Even better? His sixth palette, Ultimate, gives him an INFINITE POWER BAR AND REGENERATING HEALTH. Havefun.
Kickhopper and Punchhopper, brought to us by Jaki, double-team you. You can only hit one of them at a time, but they'll BOTH go after you—-you'll be focusing on Kickhopper, for instance, and then Punchhopper will appear behind you and start bashing your head in. Kickhopper also has the nasty habit of knocking you to the floor and stepping on your face. Oh, and just like with Kuuga, they WILL kill you in Rounds 2 and 3 if you beat them in Round 1.
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.
Speaking of Archetype Arcueid, Current Code makes her an SNK Bossin mook clothing. In this game, she is a separate character named Archetype Earth, who sometimes hijacks your arcade run as a murderously overpowered character with her unique Eclipse Style which gives her auto super meter gain + 0-cost supers. Supers which include screen-length projectiles which she can spam with gutso. The only saving grace is that if you do run into her and lose, you still continue with your arcade run.
Touhou (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 Objectnote unblockable and ungrazeable beams that give you about half a second to read and dodge, and Final Boss Suika Ibuki's Pandemoniumnote Death In All Directions at its finest.
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 Hinanawi 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 fan-made 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 of all 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.
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. Unlike Yggdrassil and Nereid, however, 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 spellcasting you can't stop the spell. 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 that is just as absurd as it was in Tales of Vesperia, or going into Overlimit 2 so he can kill you faster.
Ougon Musoukyoku CROSS 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 on 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.
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.
Little Fighter 2 has Firzen and Julian. The former is one of the fastest characters in the game and has a large range of hi-damage homing attacks, including a powerful ice/fire explosion that can't be interrupted, has a massive attack radius and fires homing projectiles. Julian has a Wave Motion Gun special with absolute priority, extremely powerful basic projectiles with slight homing abilities and another massive explosion, and he also has to be hit twice in rapid succession before he'll take damage or even flinch. In Stage Mode, you fight both of them with a small army, and even then your chances are slim.