M.U.G.E.N

"If you're looking for the character called "Mugen", look here: Samurai Champloo"



"Mugen" is Japanese for "infinity". M.U.G.E.N, however, is a freeware 2D fighting game engine designed by Elecbyte, written in C with the Allegro library.

The engine was originally released in July 17, 1999. Beta versions of it were made to work on DOS, Linux and Windows platforms, distributed through their website. The engine allows users to insert created characters, background stages, and other game objects through interpreted text files, graphics, and sound compilations to create a functioning fighting game similar to commercial games. While the engine is set up primarily for fighting game development, several other game types have been developed using it, including shooter and platform style games. Officially, Elecbyte claims to have forgotten what the acronym M.U.G.E.N stood for, but the readme documentation states that its meaning referred to the days when the engine was meant to emulate shooting games as opposed to fighting games.

The engine allows anyone to create characters, background stages and other game objects through interpreted text files, graphics, and sound compilations. It supports various types of audio formats such as MP 3 and MIDI initially, although it can be configured to play various audio formats via Winamp plugins, such as ADX and OGG, as background music during gameplay or at other points such as an introduction or the select screen. The engine allows for most of the same type of functionality found in most any commercial 2D fighting games, up to and including close recreation of those games' characters and gameplay.

Nowadays, though, almost all of the M.U.G.E.N sites have either not been updated since 2010, or have been shut down. Because of this, finding certain characters is almost impossible.

DOS and Linux

First released on July 17, 1999, M.U.G.E.N was initially created for MS-DOS. Development of the DOS version ceased when Elecbyte switched to the Linux platform in November 2001. For a time, Elecbyte had posted a request for donations on their site to legally obtain a Windows compiler to make a Windows version of M.U.G.E.N. However, the development group discontinued the project in 2003 and shut down their site. Later speculation pointed at leaks made public of a private Windows-based M.U.G.E.N beta that was provided to donators.

Windows version and subsequent hacks

The private WinM.U.G.E.N beta contained a two-character roster limit, locked game modes, and nag screens. With the beta leaked and Elecbyte gone, a "no limit" hack that removed most of these limitations was made available in 2004 by Rou Hei, followed by subsequent updates to deal with bugs and other issues. This version of M.U.G.E.N. is functionally the same as the last Linux release, though with subtle differences and unique issues, mostly revolving around proper music and music plugin support. Because of the changes between the DOS and Linux versions of M.U.G.E.N however, many older characters required at least the SFF files to be modified to show palettes correctly (notably on portraits) as well as some changes in how certain CNS script controllers functioned, causing some minor upset and those that could still run the DOS version in some form sticking to that, as well as DOS patches to downgrade characters to be compatible with the older version of the engine.

In May 2007, a hacked version of WinM.U.G.E.N was released by a third party that added support for high resolution stages (like those seen in Guilty Gear X) at the cost of losing support to standard resolution M.U.G.E.N stages. Later that month, another hack was done to add support for high-res select screens. In July 2007 another hack created by Sion and Kung Fu Man based on the last high-res hack allowed for only the select screen to be high-res and not the stages. In December 2007, a hack from an anonymous source allowed both low-res and hi-res stages to be functional in the same build, requiring only a single line of code to be added to hi-res stages.

Elecbyte's website and the return of the M.U.G.E.N engine

In mid 2007, Elecbyte's site returned, though not without some controversy as to the legitimacy of it, as it only showed a single logo with Google ads on the side. On July 26, though, a FAQ was added to the site. This FAQ went on to claim that they would release a fixed version of WinM.U.G.E.N before major format changes in the next version, and noted the formatting changes would remove compatibility in regards to older works: "Do not expect old characters to work. At all."

Despite some widespread agreement that the new site was a fake, things changed roughly two years later, when a new release candidate, MUGEN 1.0, was added to the site, with Open GL support as well as proper HD display options, victory quotes, improved (and growing) stability as a whole. The claim of widespread incompatibility of old works with this engine turned out to be false, as Elecbyte took steps to ensure that at the very least properly coded characters would not malfunction in the new engine (or would require minimal updates), though screenpacks are not necessarily subject to the same rule. As of January 2011, MUGEN 1.0 is no longer in the "Release Candidate" stage, and MUGEN 1.1 is currently in the alpha testing stage.

Clone projects 

When development of the WinM.U.G.E.N  engine stopped, several clone projects started to try and duplicate the functionality of the engine from scratch, such as ShugenDo, InfinityCat, xnaMugen and Open Source Mugen. Some of them presented online gameplay capabilities, a feature many users have sought after. Some clones currently in development are IKEMEN, its cousin BIJIN, and Paintown.

For more information, check out these websites:


 * Elecbyte's website.
 * The Mugen Fighters Guild (The basic start point for many MUGEN players. Highly recommended if this is your first time using the engine.)
 * Mugen-Infantry (A branch forum from the Guild, started around 2004 by DJ-Van, the guy who created the EVE Battle screenpack, and some other guy named Aztec Soldier who has since abandoned his admin duties due to a massive addiction to Halo. Most notable for its constant server downtime and maintenance throughout the years. Has figuratively gone through hell and back, as the entire site was shut down due to Aztec not paying the bills, but it was eventually revived on Blogspot. In 2009 a revolution broke out when the Random Insanity section was removed, which caused the formation of Genesis, as shown below. It has since been brought back, but with roughly half of its supporting members gone. The forum is currently back up and running.
 * Trinity Mugen (Created by Vans, Jesuszilla, and Fusion around 2005, it is as its name suggests. Home of many a worthwhile character and will provide hosting services if necessary). Forum is not much active, most of the action is at the IRC chat.
 * Random Select (A large database for characters and stages. Currently home to the BIJIN engine, an offshoot of the MUGEN clone IKEMEN.)
 * MUGEN Genesis (Created by Gamefreak202020. No longer very active.)
 * Stupid Dope Mugen (Product of Crazy Koopa and MC2. Sadly not quite as active as the other places.)
 * MUGEN Motherland (PrinzJanus' Forum, formerly known as PrinzMugen). Built initially as an alternative to more serious forums, Motherland presents a more casual tongue-in-cheek approach to the engine, focusing more on the playing aspect than actual serious creation and testing. It reformed itself due to complications with the old hosting.
 * Phantom Gs (MOTVN and Hank Venture's community. Formerly welcome to the public; registration is now closed.)
 * http://mugencharacters.ucoz.com/ - One of the larger databases of MUGEN characters available today, it has just about every character ever made, including some that are otherwise all but impossible to find at all (other websites just list them as being "offline," or worse, they're only hosted on Phantom Gs). Unfortunately, as a corollary, it has just about every character ever made. Additionally, it hosts its own copies of everything, which annoys no small part of the community; CTRL+F "Warehousing" below.

For the sake of not turning this article into another list of character tropes, please avoid adding entries for characters which aren't exclusive to Mugen, as tropes associated with characters from existing series can have theirs listed in their series' page.

A-C

 * Accentuate the Negative: The defunct Doki Doki MUGEN review site. Other creators have been known to indulge in this at times when they give feedback.
 * Aerith and Bob: When you have a crossover between many games, this was going to happen.
 * Amazing Technicolor Battlefield
 * Anachronism Stew: When you have characters from fighting games that take place during different time eras, this happens.
 * Assist Character: Some characters have built-in assist characters (usually referred as Strikers like in King of Fighters), some of them like Juza who had them in source game, but the majority of characters with built-in assist characters have them because of the engine's limitations.
 * Attack of the 50-Foot Whatever: Doable, in the vein of Apocalypse from X-Men Vs. Street Fighter, with proper application of art and hitboxes. Bizarrely averted with Godzilla and Gundam fighting characters... buuutttt there are some stages that allow you to do this (with, strangely enough, Godzilla and Gundam stages). Same goes with EVA and Primal Rage characters.
 * Attention Whore: Very common in the community.
 * Author Filibuster: Some of the MUGEN videos have this problem, as do people creating custom characters - especially from scratch. There is also the popular practice of coding a character to crash against opponent characters the author does not like, or making videos solely about beating up a character.
 * Bloody Murder: Any Mugen video which at the end include Fatality, Zetsumei Ougi, Any Finisher Move with the original characters of Andr?s Borghi, etc.
 * Giygas' fatalities, which are jacked from EternalChampion's Overkills - but are somehow much more scary, even though they're relatively untouched straight rips.
 * Bruce Lee Clone: Bruce Lee himself is in there.
 * Calling Your Attacks
 * Chainsaw Good: Sadako look-alike and general horror movie tribute character, Ella. Duke Nukem has a special palette that gives him the Doomguy's chainsaw. After he blows up Doomguy and steals it.
 * Cherry Tapping
 * Chuck Norris: Comes with no hitbox for extra-invulnerable goodness! As the Defeating the Undefeatable entry demonstrates, though, he's not entirely invincible.
 * Cloning Blues: There are many, many edited Kula and Len clones out there.
 * Combo-Platter Powers
 * Combos
 * The Computer Is a Cheating Bastard: Prevalent in some characters to an uncomfortable extreme. The good news is that some of the more diplomatic creators will include multiple levels of AI for their characters, and for the rest, MUGEN's customizability lets you curb the more insane AI yourself IF you know what you're doing.
 * Counter Attack
 * Crossover: Very often used for this, although gameplay styles won't necessarily mix well, particularly when Guilty Gear is involved.
 * Cute Monster Girl

D-F

 * Damn You, Muscle Memory!: The possibility of a MUGEN build having characters coming from different source games (complete with distinctive control schemes of such) tends to get some players mixed up when getting to know or use new characters.
 * Death of a Thousand Cuts: There are many characters who's attacks will hit the 999 combo meter. It's mainly overpowered characters.
 * What's a little funny is that in Daniel's readme, his goal is "to achieve 1,000 hits in MUGEN."
 * Defeating the Undefeatable: Over and over again. Chuck Norris, a literally invincible Lethal Joke Character based on Chuck Norris Facts. He actually has been defeated before. Before that? He maimed several undefeatable characters with the same hitbox-less advantage, such as the previous Oni-Miko. And people have been trying to one-up Oni-Miko and everyone else since.
 * Both Chuck Norris and Oni-Miko-Z have fallen to the Debugger character, two floating strings of numbers that "delete" the opponent's root file, causing them to be read as nonexistent and dead.
 * Demoted to Extra: The Blaz Blue characters remain almost entirely unaccounted for here. So far, there's a version of Jin known as Ares who plays like a bad Ky Kiske cover band and a recurring meme in which Rugal slaughters Ragna in the prefight intro. Recently Hakumen, Tsubaki, Hazama and the original Jin (with ice) have been ported in. The lack of Blazblue conversions is caused by the large size of the sprites (though there are ways around that) and that adapting the sprites to the proper size does not necessarily make it possible to translate all of the physics and mechanics properly.
 * Depending on the Writer: If about two or more makers share the characters they've converted, don't expect them to be both exactly the same.
 * Few makers also are quite creative in their takes on certain characters. A good example would be The_None's Possessed Heita, who has a mode that comes with Captain Falcon's moves and voice. (Influenced heavily with the works of 3ha, which are almost 2 in 1.)
 * Did You Just Punch Out Cthulhu?: If you can beat Giygas, then... well, you have done this. IF you can beat him....
 * Digital Piracy Is Evil: Two forms of it.
 * "Warehousing" is the practice of hosting a character on a website without the creator's permission. In some MUGEN circles this is regarded as a disrespectful and dishonest practice, while others simply aren't concerned about it.
 * The second one, much more subject to ridicule, is known as "spriteswapping". The "creator" takes another character, and replaces the original character's sprites with his own sprites. In particularly bad cases, the spriteswap will retain the base creation's gameplay elements even if it doesn't match the spriteswap's playing style. Many spriteswaps also tend to have jacked-up stats, making them cheap and over-powered, like so.
 * One creator attempted to copy-protect one of his characters against spriteswapping by, at the start of the match, checking to see if the creator and/or name had been modified in the fighter's .def file. If it detected a change, then it would halt the match and throw up a short Refuge in Audacity skit featuring Pac-Man before displaying "Quit trying to steal my shit!"
 * Subverted in the case of sprite-ripping characters from games (such as Ryu) and using them in MUGEN. Capcom was asked about this early in MUGEN's existence, and the company stated that they consider it a form of fan art (so long as no one sells the characters, of course). Pretty much every other company has followed Capcom's attitude.
 * Dysfunction Junction
 * Early-Bird Cameo: Andres Borghi's horror-themed creations (in addition to two new characters) became stars of their own MUGEN-engine full game.
 * The End of the World as We Know It: This is what the Death Star uses as its strongest attack.
 * Eighties Hair: Bebum Ryo.
 * Eldritch Abomination: Giygas.
 * Everything's Better with Penguins: The MUGEN China penguins.
 * Everything's More Injurious With Kittens: One of White Len's attacks.
 * Evil Super Hyper Orochi SSJ9 God Rare Bimmy and Jimmy Devil Satsui No Hadou Mecha Counterpart: There are many examples of these kinds of characters in MUGEN. Let it be left at that.
 * Played with in Rare Akuma's name and in Giji Ultima Gouki Oddity's full name.
 * Rikard attempted to deconstruct this trope with Slightly Pissed Off Ryu. Not only did it fail, but Rikard became pigeonholed as the creator of this character rather than his original characters, much to his displeasure.
 * Exactly What It Says on the Tin:
 * Don Drago's Zangief With Missiles edit. It's Minmei's KOF Zangief...with missiles falling from the sky.
 * Big Glitchy Retarded Tiger Woods. The fact that it's an overpowered spriteswap of Claymizer's Chansey doesn't help one bit.
 * Extremity Extremist
 * Fan Disservice: THIS.
 * Fartillery: Peter Griffin uses farts as a flamethrower (known as the Anal Torch) and also uses farts like a hadouken.
 * The goblin character Menelikke does the same in his super. There's also the giantess Delilah who, in one of her alternate versions, has a full screen gas attack.
 * And there's also Gustavo, whose only attacks are... well, farts, when attacked.
 * Most_Mysterious played with this. Some of his characters have moves that have farts as a hitsounds (notable examples include Dink Smallwood's (who doesn't seem to even look like the character he's supposed to be.) Big Mother Ducker (also appearing as Skullman's striker) and Omega Tiger Woods's Shrimp Bus supers).
 * Iggy's throw has his Stand grabbing the opponent and Iggy jumping up to said victim and farting on his face.
 * Finishing Move: It's not uncommon for a character's super to be used as this. And that's not counting characters from games that explicitly have finishing moves, such as Mortal Kombat, the Hokuto no Ken fighting games, and Sengoku Basara.
 * Frickin' Laser Beams

G-I

 * Gainaxing: Despite not bouncing at all in the actual Street Fighter games, Warusaki3's Rainbow Mika does this.
 * Game Breaking Bug: Certain matchups can lead to one character being unable to land a single point of damage on the opponent, both characters being unable to damage each other at all, or outright malfunctions in the engine, due to the different codes used with each character and/or sloppy coding.
 * Gender Flip: See Rule 63 below. There's also the infamous Midnight Bliss...
 * Giftedly Bad: That seems to describe GooGoo64 pretty well.
 * It's also pretty safe (Lickspittles aside) to assume Alexlexus being this.
 * Glass Cannon: The Space Invader from Space Invaders. It has only one attack, a laser that instantly vaporizes the enemy if unblocked. However, it will go down in one hit.
 * A God Am I: Any "God" version of a character. Happens literally with the Primal Rage trio of Diablo, Talon, and Vertigo, who, uh, are gods.
 * Gorn: Several characters in the MUGEN roster, such as those from Mortal Kombat, are fond of gory ways of finishing off opponents.
 * Green Hill Zone: Several people have even created the Trope Namer.
 * Green Thumb: Hashi
 * Man-Eating Plant: Hashi, technically, is one. Samurai Shodown Konoha uses one in her Zetsumei Ougi.
 * Godwin's Law: The "X-Form" of The_None's Skullman has a counter move in which he hits you while being shaped like a swastika.
 * And yes, an Omega Adolf Hitler character exists.
 * MC2 as EvilSlayerX5 epically Godwin'd himself by changing his background into a swastika.
 * Hailfire Peaks
 * High-Pressure Blood: With Mortal Kombat and Samurai Shodown characters converted to the engine, this was bound to happen.
 * Hit Points
 * Cast From Hit Points
 * Hurricane Kick
 * Hyperspace Arsenal
 * I Am Legion: The infamous Vyx seems to do this, which is one of the many reasons people despise him.
 * Improbable Weapon User
 * Deadpool has a sheep with a cannon to its back in his special.
 * Garfield uses hot dogs as projectiles.
 * Pingu and Finn use snowballs as projectiles.
 * White Len has been known to attack with kittens.
 * Dancing Banana uses oversized bananas as projectiles.
 * POCKET SAND
 * Spongebob uses bubbles and Krabby Patties as projectiles.
 * Princess Bubblegum uses beakers as projectiles that explode on impact when it hits the ground.
 * Sonic uses rings as projectiles.
 * Homer uses doughnuts as projectiles.
 * Peter uses beer bottles and his lit farts as projectiles.
 * Adam Admuson can use a Game Boy, a spiked ball, and a raygun as projectiles.
 * Daniel can use some kind of...thing, and Cirno as projectiles.
 * Bob and Cartoon Guy can use rocket fists as projectiles.
 * Chaos beat Peter to the punch and uses a slow-moving, noxious cloud of fart.
 * Bridget uses modified yoyos.
 * Taz uses burps.
 * Improvised Weapon
 * Rorschach. Hairspray. Cooking Fat. Grappling Gun. Toilet. Numerous Others. Hurm. Deconstruction. Lethal and Gruesome Results.
 * Inevitable Tournament: it had to happen. Some MUGEN forums hold tourneys for fun. While most follow a standard format (usually 1 vs 1 or 4 vs 4), some have fun twists on the genre.
 * Instant Death Radius: Oni-Miko-Zero. Literally. Put her up against any character (save for a few) and that character is DEAD even before the battle starts...
 * The "Debugger" character uses a code that somehow deletes the opponent's root state, causing them to be read as nonexistent and thus KO'ed before the round starts. So far, it can beat Oni-Miko Zero and Chuck Norris with no effort, and is possibly the cheapest character ever.
 * Did somebody say "Salvation Orochi"? Because I think somebody said "Salvation Orochi".
 * Internet Mimic: Back in the day when Judgespear was still active, since the main characters he used were Homer Simpson and Peter Griffin, he made most newcomers to grab Homer and Peter (a practice now frowned upon by more experienced players).
 * Invulnerable Attack: Known as "Infinite Priority" here. A favorite of SNK Bosses, cheap characters, as well as "retarded" characters.
 * It Got Worse: EvilSlayerX5. First, he used to be some loner who disliked accuracy. Then, after he created his less than stellar Rugal_E which multiple people criticized as a game-breaking and buggy character, it all went downhill from there. He actually believed at one point believed that there was a secret government controlling the masses to hate him and his characters.

J-L

 * Jerkass: A prominent character trait of certain community individuals.
 * Joke Character:
 * Gustavo
 * The Kid from I Wanna Be the Guy. He plays exactly like he does in his original game, so he's not going to be killing Chuck Norris anytime soon. Though he can get help from his former enemies, including The Moon, Spikes, and of course those giant anti-gravity cherries, they are all just as capable of killing him as they are his opponent.
 * Kyubey. He doesn't attack, defend, or even move after starting the match. Justified in that, considering what he actually does in the series, he deserves every living second of pain.
 * Lethal Joke Character: The Dopefish, Zeeky H. Bomb, Slot Machine, The_None's Sue Sakamoto (aided by ), Neco-Arc
 * There's also Rolento's Yoshi, whose movelist consists solely of
 * A certain take on Jam from Guilty Gear knocks the opposing character onto a bed and humps until their energy is drained, resulting in either a DKO or a victory.
 * The Killer Whale.
 * One of The_None's April Fools' Day releases, Noah, whose basic attacks - when low on health - would No wonder The Nerd was right...
 * Gay Bahamut/Primeus, The God Of Retarded Characters by RicePigeon, most of whose attacks involve notoriously "retarded" characters.
 * There's also Giygas/Ozma, created by fhqwhgads7 and supposedly inspired by Primeus, which is an April-Fools'-joke-character-turned-boss. It's basically a gigantic floating jawbreaker that starts off with Giygas' attacks... and then imitates various Youtube Poop characters as it loses health and layers.
 * Vans' Rock Howard, who has the voice of Urien and whose MAX2 super move destroys the universe, crashing your program in the process.
 * Omega Tiger Woods, who can and will soundly pummel almost any character he comes across as long as that character isn't another Omega Tiger Woods. Where does he get that Shrimp Bus from, anyway?
 * Someone made a version of Mario for MUGEN called "NES Mario". He can only attack by jumping on enemies and he dies in two hits (if you don't press the button to turn into Super Mario again at the expense of some of the lifebar). However, there's something that makes him lethal: Fighting game characters flinch win hit, Mario does not. If you get a window of opportunity, you can just keep on stomping your foe and finish them off in less than a minute.
 * Someone also made the classic version of Pac-Man. All he can do is move across the stage and munch on whatever gets in his way, but that's all he needs to do. God help you if he gets hold of a power pellet...
 * One of the characters used as a "cheapie-buster" in earlier times was the Metool, the Mascot Mook from Mega Man. It had half the attack and defense of a regular character (and died twice as fast), but it was short, making it hard to hit, could spam a Spread Shot from afar, and it could use its signature helmet guard. Oh, and that giant metool that instantly squished his enemy.
 * Saggot, aka Bootleg Sagat. An edited Sagat that plays like the infamous Street Fighter II bootlegs. What this means is a whole new level of Tiger Shot spam, ridiculous comboability, and he even crashes MUGEN on a regular basis. To further rub salt in the wound, his theme from Street Fighter 1 perpetually plays during his fights, overriding your music, and his victory pose references the famous Cornflakes line from the Street Fighter cartoon.
 * Flame Hyenard. Just... Flame Hyenard. You WILL BURN! BURN! BURN TO THE GROUND! if you fight him.
 * Zeori and NM Ori, two entries in Trinity MUGEN's "Iori contest".
 * Kamehame Hadoken: What's a fighter without it?
 * Ki Attacks
 * Kill It with Fire
 * Kill It with Water
 * Kiai: Being a fighting game engine, there are many examples. The most particularly notable one is the Jo Jos Bizarre Adventure "WRYYYYYYYYYYYYYYYY!" (Used when anybody uses the Steamroller or when Chuck Norris drops the sun on his enemy.)
 * Kung Fu Jesus: As a MUGEN character. Yes. So are God and Satan, courtesy of Adult Swim's Bible Fight.
 * Lazy Artist: Rather common, especially when new Shotoclones are involved. However, this is sometimes justified, when creators use characters as bases for their distinctive creations (e.g. the majority of the MvC-styled Mega Man characters, which use Mega Man as a base).
 * Lethal Lava Land: Diablo's stage, among others.
 * Loads and Loads of Characters: There are so many characters out there to download and play with.

M-O

 * The Mario: Amongst examples, there's Kung Fu Man, a character that comes with any downloaded copy of MUGEN (mostly as a base for making characters, and a coding example) that eventually became the mascot of the engine.
 * Mega Manning: MegaMari
 * Mighty Glacier
 * Moe Anthropomorphism: The OS-tans are in MUGEN already.
 * Musical Assassin: Yoma Komatsu.
 * Hatsune Miku uses her voice as her weapon.
 * My Overkill Is Better Than Yours: This is the basic premise of the EXTREMELY cheap characters. (e.g. Chuck Norris) "taking part" in the Nuclear War, constantly being updated to beat each other. If any one of them is defeated, expect their update to have immunity to the move that killed it. It got to the point where they became capable of winning matches against regular characters before the match even starts.
 * Ninja Pirate Robot Zombie: (oh yeah)
 * Nintendo Hard: A lot of AI patches go here. For a specific example, the work of Misobin_ISM. He turns mild mannered, but still challenging, characters into absolute monsters. His patch for Vergil basically pits you against an encyclopedia of his combos, Dio lays you out with some crazy tandems and abuses his teleport while defending, Geese will counter all of your moves and force feed you a Deadly Rave, and Shin Akuma is as insane as you would expect. There is also Hutano, who basically unlocks the true power within 9's Melty Blood characters and shows you some of the most nightmarishly evil combos ever seen.
 * Muteki's Guilty Gear characters are built with aggressive AI that takes full advantage of the computer's natural advantage against human players. It blocks most attacks without a second thought and links together very long strings of attacks to make sure that the human player can't fight back for more than a second.
 * For a non-fighting example, pitting fhqwhgads7's The Kid and Yukari Yakumo together will start the match with The Kid in a scrolling obstacle course. Keep in mind that like in the game, The Kid dies with one attack, and you can't fight Yukari unless you get through the course. Even then, the match simply becomes a boss fight against Yukari.
 * Well, if you don't count her pulling out Primeus.
 * No Ending: Most characters do not have ending storyboards for completing arcade mode.
 * Non Standard Character Design: If your roster contains characters from games with wildly different art styles, this is bound to happen.
 * Norio Wakamoto: There's CV-Wakamoto, some... thing with Wakamoto's voice and moves taken from characters Wakamoto has voiced. A edit of Kung Fu Man was released with, you guessed it, Wakamoto's voice. It had most of the moves of Wakamoto's characters, and is incredibly broken.
 * Nuke'Em: The A-Bomb, a Lethal Joke Character who can completely OBLITERATE pretty much any other character that isn't as overpowered. It can, however, be defeated by a certain character, as well as a few others that surpass it in cheapness.
 * The Zeeky words and the Random H-Bomb in Zeeky H. Bomb's arsenal.
 * One-Hit Kill: Any character that possesses an extremely convenient one to use is almost always considered to be extremely cheap and/or a Lethal Joke Character. Examples include:
 * Rare Akuma's Shun Goku Satsu.
 * Many of the attacks that Chuck Norris uses, not just his Roundhouse Kick.
 * Each of Gulthor's ovepowered characters have at least TWO of these.
 * Killer Whale, Cheep Chomp, and Dopefish do this to your character if they eat him/her.
 * Oni-Miko-Zero does this to her opponent BEFORE THE BATTLE BEGINS.
 * Similar to her, Debugger does this to its opponent. Except that his works on pretty much everything (Oni-Miko-Z included).
 * Death Note: Light Yagami writes his opponent's name in his Death Note as soon as the match begins. Fans of the series can probably guess what happens next.
 * Zeeky H. Bomb has two of these. One (Random H-Bomb) only works as a counter, and the other severely damages Zeeky himself.
 * Pingu's most devastating attack has him sink into the ground as the lights go out and he calls to his opponent. Then, the lights turn on and he reappears in front of his opponent, wings upraised. Instant KO! His Shun Goku Satsu is usually a KO, too.
 * Master Mecha Sonic has "Hyper Kamehameha", which, while truly being 1 hit, actually does over 999 hits as far as the counter is concerned. Considering Mecha Sonic's record in Super Mario Bros Z, this isn't exactly a surprise that he gets a move like this in Master form.
 * The Space Invader has this both ways. If his laser gets you, you're instantly vaporized. If you hit him once, he's instantly vaporized.
 * One-Hit-Point Wonder: The Kid from I Wanna Be the Guy. Complete with blood spatter and GAME OVER. PRESS "R" TO TRY AGAIN.
 * Subverted in later versions where he gains super armor while facing himself.
 * One-Winged Angel: Not just Sephiroth's final form, either; there's a MUGEN creator who's called just that!
 * Original Generation: While a popular use of the engine is adapting characters from existing games, many people have created original characters using the MUGEN engine - SeanAltly is a prime example, as well as Andres Borghi, Reuben Kee, Kung Fu Man, Aiduzzi and Rikard.
 * Overly Long Gag: Renowned MUGEN creator aokmaniac13 is guilty of this in his 'Mind Games' video series. Generally, they focus on a major flaw in the character's AI, such as never guarding low or behaving awkwardly when he does something simple, like crouching. As you might've guessed, they run for all 99 seconds on the timer, and for two rounds to boot.

P-R

 * Panty Shot: Potentially any girl wearing a skirt; whether they play this straight or wear a Magic Skirt depends on the game they're ripped from, the franchise they come from, and/or the character maker's personal preference.
 * Paper-Thin Disguise: EvilSlayerX5 as SilverJeric. Not surprisingly, everybody saw through it...
 * Petting Zoo People: Izuko Chrysoberyl and many other characters.
 * Power Creep, Power Seep: Tends to happen when creators don't strictly adhere to the idea of converting characters exactly as they were in the source game. Seravy (the "creator", not the character) actually tries to avert the creeping trend, but is often ridiculed for the results.
 * The Power of Rock: Yoma Komatsu rocks out on her guitar and calls on the rest of her band to beat the crap out of people.
 * Suzumiya Haruhi calls Hokago Tea Time as one of her special abilities.
 * Hatsune Miku uses her songs.
 * I-NO's Guitar and Demon Amplifiers.
 * Pragmatic Adaptation: While most characters are either labelled as accurate but aren't, there are a number of characters that are deliberately not meant to be accurate, such as CCI Ironmugen's Ryo or The_None's Shaq. In some cases, accuracy may NOT be a good thing.
 * Real Men Wear Pink: Since it's easy to customize the colors of the character palettes, it's just as easy in most cases to make pink clothes for even the manliest of men.
 * Red Oni, Blue Oni: Anything involving Arpa/Chainsawdentist will inevitably have him as the Red Oni, except for his videos with Ashram VII, which has more of a Crimson Oni Scarlet Oni dynamic.
 * Rule of Fun: The only explanation for the many, many offbeat characters out there. Considering you can pit Peter Griffin against Fat Albert against Sonic the Hedgehog against Michael Jackson against Chuck Norris if you want to, no other explanation is really needed.
 * Rule 34: There is a whole sub-culture of hentai related MUGEN creations, including characters, stages and the like.
 * Similarly, there are nude versions of many fighting game gals out there.
 * Rule 63: Kyoko, Goeniko and Zeroko (both original and clone). Gelato is a rare female-to-male genderflip of Kula Diamond, and there is a "Shikiko" and a "Kyko".
 * Ryuuoutan happens to be the Dragonlord from the Dragon Quest series if he/it was a cute girl.
 * Ryona: Some MUGEN vids put out by creators explicitly cater to this fetish, with characters doing goretastic fatalities on their female opponents being particularly popular.
 * Ryu and Ken: Ryu & Ken, the Trope Namers are there (of course), along with their Alternate Company Equivalents, Captain Ersatzes and Expies.

S-U

 * Self-Deprecation: When not doing the below, Rikard, the Italian creator who made several characters heavily edited from KOF and Slightly Pissed Off Ryu (for more details on the latter, see Take That entry below).
 * Serious Business: Despite appearing to be the go-to answer to questions like "Who'd win in a fight between Optimus Prime and Bill Clinton", a vast majority of the community can take certain matters way too seriously, such as the "cheapness" of certain system features.
 * Shape Shifter: The_None released a version of Kishima Kouma dubbed "Shadow Kouma" that at first appears to be a perfectly innocent custom take on the character. Then you actually see him in action
 * And before that, there was Cerenas's Sihon (who transforms into various Samurai Shodown characters) and the collaboration between Andre Lopes and Ryan Kerns in the form of Mugena (who mainly transforms into various female characters).
 * Shang Tsung himself as well. OMEGAPSYCHO's version deserves special mention, as he managed to make him able to transform into nearly every MK1 character but Goro. Juano's Shang Tsung goes this way too, having every MK 2 character, including Jade, Noob Saibot and Smoke, but excluding all bosses.
 * Shotoclones: A lot.
 * Shout-Out: Kamek is loaded with them. He can summon one of three Pokémon at will and can use fatalities, one of which is directly based on one of Smoke's. His Troopa Rush super is admitted in his readme to be a takeoff of Tron Bonne's Lunch Rush special. Some of the objects that can fall from the sky in his Switchblock Drop super are the Egg-o-matic, the Master Emerald, a cow, and Lavos. And he can use Ultima.
 * Silliness Switch: Homer's Drunk Homer mode combines this with Turns Red.
 * In AWESOME FASHION.)0:28
 * SNK Boss: Depending on the creator, the AI can be written in such a way that SNK bosses or any normal character can turn this trope Up to Eleven.
 * Perfect Play AI: Every Mortal Kombat boss from the 2-D games are in there too. And that includes Motaro.
 * Some Dexterity Required: Tends to occur as a reflection of the source game (e.g., "The Pretzel", the Fan Nickname for Geese Howard's Raging Storm command), although editing the files to change the command to something easier is a simple matter.
 * Speaking Simlish: Pingu
 * Spiritual Successor: The readme claims that inspiration for the engine was taken from the PC homebrew Street Fighter II clone SFIBM (at least in part). It also had a modular engine that facilitated editable characters to the point that some gained new moves and others were completely broken. Not unlike many MUGEN characters.
 * Stealth Parody:
 * Stringy Haired Ghost Girl: Ella and Noroko.
 * Strong Flesh Weak Steel
 * Sturgeon's Law
 * Stylistic Suck: Kung Fu Man's intro and ending storyboards that come with the engine by default qualify, looking like a kid's crayon drawings. Most_Mysterious's (of Omega Tiger Woods (in)fame) entire creationhood can be basically summed up as this.
 * The Dancing Banana also counts in a way, what with being a rather pixelized character, but the reason for this is because his graphics are based off the original emoticon.
 * Summon Magic: Some characters do this as a super attack by calling in a reinforcement to perform an assist (see Kamek in the Shout-Out entry above).
 * Hatsune Miku takes this Up to Eleven with her super singing attacks - if she sings a soundtrack from a well known franchise, a character from the franchise comes in to perform the assist. And given how many there are...
 * Super Move Portrait Attack: The_None's  deserves special mention, for that he has a super move that.
 * Swiss Army Character: Most of 3ha's characters have custom modes based of completely unrelated characters. Among examples:
 * His Bishamon with Jin Saotome AND Galford grooves.
 * Dhalsim with a Brocken groove.
 * Sieger with a Blodia groove.
 * A Sentinel with Fio piloting it. Fio can actually eject from it so she then plays exactly like in Metal Slug series, complete with her being a One-Hit-Point Wonder.
 * Zangyura, a bastard child of Zangief and Godzilla of all people has a "Gorbachev" mode.
 * And his latest (so far) creation, Zangeese (who also comes with an optional Athena movelist....with the voice of M. Bison).
 * He has a Heavy D! there, which seems normal....until you hold start and he gains K's moveset.
 * 3ha's Genjuro Kibagami uses a mixture of the Slash/Bust system of IV with the gameplay of V Special, complete with Zetsumei Ougi. Holding start while selecting him, however, lets you control his frog, which has M. Bison's moveset and voice.
 * A non-3ha example: the aforementioned The_None's Possessed Heita, who comes with a Captain Falcon mode.
 * "EVIL Sub. Rep. Scorp." It's a failed attempt to mash Sub-Zero, Reptile and Scorpion into one character. Although it does weak damage, it's too damn fast, spams a damaging teleport, takes advantage of projectile spamming to freeze the opponent, and many, many more bugs.
 * Take That:
 * Rare Akuma is the mother of all Take Thats to badly done "Shin", "Orochi" and "Evil" edits of many characters. He has an abundance of special effects, is effectively immortal, and can kill most characters in the space of a few seconds.
 * Some guy named thelordanon created an edit of Rare Akuma and dubbed it Giji Ultima Gouki Oddity (aka. Giji Rare Akuma, aka., in his own words, "Giji Penultimate Light Flawed Ouroboros Daydream Disorderly Demigod Ascended Ultima Gouki Oddity 8999 AD Mark VI Beta (BITCH)"). Supposedly he created it as an experiment to see how far people could tolerate Rare Akuma's... Rare Akumaness set to some number above 11.
 * There's an entire full game being made with nothing but Akumas with completely different movesets. The creator of the project, Basara, admitted he's doing it because he's sick of all the Akumas going around.
 * MUGEN Gangbang/Gankbank/Tennis, anyone?
 * Rikard's most prolific creation is Slightly Pissed Off Ryu, a parody of the various Shin, Evil, Orochi, Violent and Holy Ryu edits on the internet. Rikard's "story" basically sets Ryu as a McDonald's bum, depressed and physically out of shape after finding his wife Sakura cheating on him with Akuma (he has appropriate, and hilarious, victory and winquotes against both of them). His Hadokens are usually a pathetic short range burst, his Shinku Hadoken may u-turn RIGHT BACK INTO RYU'S FACE, he falls flat on his back after a Shoryuken, he sometimes breaks his ankle when he does his trademark Hurricane Kick, and one of his other attacks has him lobbing either a McDonald's meal or M. Bison's corpse at them. Most Ryus run on graphics over gameplay. This Ryu? Runs on pure Rule of Funny.
 * P.o.t.S released Bison...literally. It's an actual bison with M. Bison's cap on its head. It uses distorted versions of Norio Wakamoto's voice clips from Capcom VS. SNK 2 as well as clips from the Animated Adaptation. And it's actually balanced to be fought as a boss character, having high stamina, infinite prevention measures, and a very good AI that takes advantage of the character's high power. Instead of being a Take That to cheap characters as Rare Akuma was, it's a Take That to joke characters and serious characters, simply by existing. Hilarity did indeed ensue.
 * C. Evil Ryu is one to the Mv C: EOH collab project by Arpa.
 * That Wacky Nazi: EvilSlayerX5 revealed himself as that after he changed the background of his youtube profile into a swastika.
 * There Is No Kill Like Overkill: Anything involving lots and lots of blood, characters with lots of flashy effects, and any attacks that reach the 999 combo limit.
 * Ironcommando is pretty much a top contender if not outright the Overkill Overlord. Once he became much less egotistical and willing to listen to feedback, he stopped adhering so strictly to the trope.
 * Took a Level In Badass: Pingu, Garfield, Homer Simpson, Princess Peach... The list goes on.
 * Trope Overdosed: Since it is a crossover of every fighting game in existence, this was bound to happen eventually.
 * Unwinnable: Any fight against Oni-Miko-Zero. Or Debugger (if he is on P1's side).

V-Z

 * Widget Series: The Characters from the Nijikaku fighting game by the 2Chan Image Board.
 * The game itself. We're talking about Velociraptor Gods taking on a mutant cyborg Tiger Woods that utilizes a robot claw and airstrikes. Wholesome Crossdresser nuns teamed with evil witches with truth-based magic systems that beat up UNSTOPPABLE! God-powered roid ragers that spew Uncle Tomfoolery. Inside the womb of a birthing God. Reality Warpers fighting against sadistic vigilantes. And Chuck Norris.
 * The game's still popular in Japan for this reason, and loads of Pixiv fanart based on bizarre matchups (and even pairings) have occurred, spawning things like a cross between Alice Margatroid and Cable due to their reliance on lasers.
 * Wolfpack Boss: There is an AI-only character called "Biohazard" that is basically a huge swarm of zombies, crows and dogs that all share one life bar, and killing enough of them eventually summons a Tyrant. The Alien Queen's default palette is also this; she does not appear at all in this mode, but instead sends a swarm of Alien drones to attack you, and the match only ends when you've taken them all out. The Mad Gear Gang are also available as an opponent.
 * There's also the "Strength Training" minigame, which pits your character against a swarm of Beat'Em Up-style Mooks, and is sometimes used by series creators for mook fights.
 * With some luck, you can hack stages like Super Mario as an opponent, resulting in an odd variant of this.
 * You Gotta Have Blue Hair: MUGEN allows color/palette customization, so this trope is there in spades, especially for characters based on Anime.