The Missingno



The Missingno. (short for Missing Number) is a Video Game character whose very existence is actually just a flaw in the game's internal programming. Can be considered a Good Bad Bug in and of itself, but all bets are off.

May be found in a Minus World, and often exists for the same sort of reason -- the game accidentally tries to load character data from a section of memory that is intended for some other purpose entirely, leading to the resulting "character" appearing. If a Missingno is noticeably more powerful than anything obtainable at the point in the game that it can be gotten, using it treads into Fake Skill territory.

Note that because this character was never intended to actually exist, merely encountering The Missingno can trigger an unpredictable bevy of side effects, ranging from other Good Bad Bugs to game crashes, or even Game Breaking Bugs. In the rare worst-case scenario, The Missingno can even corrupt the player's save file, forcing them to erase it and start the game over from the beginning.

Video Games
""It's a Clubberfuck!""
 * The Trope Namer is the glitch Pokémon "MISSINGNO" from Generation I. A similarly glitchy creature has a name consisting of a quote mark, the letter M, and two unpronounceable symbols. It has been Fan Nicknamed "M-Block." The glitch is actually caused by the game trying to interpret your Player Character's name as random-encounter data.
 * Missingno., its glitchy kin, and the effects they have on the game make up an impressive amount of Pokémon's Nightmare Fuel page. In fanfiction, they're often portrayed as a form of Eldritch Abomination.
 * Missingno. also has the benefit of multiplying the sixth item in your bag to 128 or 255 in quantity. For competitive battling, this is quite the Game Breaker. Cloned Rare Candies + Cloned Technical Machines + Cloned Master Balls + Cloned Medicine = A team of six in the timeframe it would take to create one Pokémon without glitching.
 * It's worth noting that, despite common belief, Missingno. is actually relatively harmless; it only causes minor graphical glitches and corrupts the Hall of Fame data (and the Hall of Fame entries aren't required for playing the game anyway). 'M, however, can do horrible things to your game if you send it to your PC at level 0, even deleting it outright.
 * 'M and Missingno. are probably the best-known examples in the series because you can encounter them without modifying the game in any way. With use of a Game Shark and a Walk Through Walls cheat enabled, however, it's also possible to run into a number of different glitched Pokémon and trainers, many of which can do serious damage to your save file if you're not careful (or just plain unlucky). This LP of Blue version details many of them and their effects.
 * Apparently, Missingno might actually be leftover data from removed Pokemon, while its unpronouncable kin are "garbage data" given form.
 * Sonic the Hedgehog 2 had a glitch where using debug mode to create a metric buttload of a certain object would cause Sonic's palette to be overwritten, turning him green, black, and one other color (which would often also be green or black). This miscolored Sonic, nicknamed "Ashura", is a surprisingly popular "character", making bizarrely frequent appearances in fan works.
 * There's also a white recolour of Knuckles in Knuckles Chaotix, nicknamed White Echidna (shortened to Wechnia), who's actually what's left when you take Tails out of the game altogether.
 * Sonic 3 & Knuckles has Blue Knuckles, who plays like a mixture of Sonic (his palettes and level routes), Knuckles (abilities), and Tails (uses his name at the end of act tally). The only ways to play as him are through hacking, Game Genie, or a massive glitch in Lava Reef.
 * Also, if you turn on Debug Mode, use Stage Select in Sonic 3 & Knuckles, go to the Doomsday Zone Act 1 as Knuckles and beat the level, the ending sequence will feature a palette swap of Sonic, Knuckles, and the Tornado.
 * Generally trying to get either Tails or Knuckles into The Doomsday through method this will make their sprites garbled up, as the game still recognizes both of them as being Super/Hyper Sonic, who is supposed to be the only character allowed to face this level and the game's first True Final Boss.
 * Since the game dynamically loads enemy sprites and tiles as you go through a level, if Sonic goes too fast while in Super Mode, he can outrun the sprite loading and cause enemies or backgrounds to be garbled.
 * The original Mortal Kombat, while it did not have a character named Ermac (it was an April Fool's Joke), did give us Glitch Reptile and Silver Goro, two glitch characters that trigger during the game's three Endurance Matches in one-player mode. Glitch Reptile occurs when you do the trick to get to Reptile during one of the Endurance Matches; you'll fight two Reptiles as a result, but the second Reptile will be a graphically glitched version of random characters in the game. You get Silver Goro when you perform a fatality on the second opponent of the last Endurance Match with Raiden or Sub-Zero, then throw your projectile at Goro as he falls from the top of the screen. Do it right, and his colors will be glitched to a weird silver for the remainder of the round. Good memories, good memories...
 * In the Amiga port of the second game, do the friendship on the morphed Shang Tsung, and you're now just controlling the lost brother of Glitch Reptile.
 * Street Fighter Alpha Anthology's hidden bonus game Hyper Street Fighter Alpha brings us hidden versions of Alpha 2 M. Bison and Sagat with scrambled Missingno sprites. They both share a partial Evil Ryu moveset, have no super meter, and cannot be hit while standing still.
 * In Ultima VI, one could grab any dead body from the enemies you kill, and have a Healer resurrect it as if it were a party member. The result is a bizarre graphic mishmash (usually depicted as a pile of floating gold coins) with an unintelligible name, now a member of your party. Stats are extremely erratic; but it was good to send on a suicide mission as a distraction.
 * A couple of these can be seen in the Dummied Out "lost levels" of Super Mario Bros. 3, such as a Koopa with Chain Chomp sprites, as well as in certain ROM hacks.
 * With the help of Game Genie codes, you can also create strange power-suits. One of the weirdest turns the player character into a conglomeration of blocks that can swim in the air (a Lakitu Cloud on the map screen).
 * In Advance Wars: Dual Strike, it is possible in the CO select menu screens to choose only one CO and leave the second slot blank, then swap the CO with itself, leaving the first CO slot blank and the second CO slot occupied. Starting the game, you are given control of a "null" CO with glitched graphics and Andy's theme song. Your CO power charges instantly and activating it will freeze the game.
 * Fixed for the European version.
 * Halo 2's "Honor Guard Councillor" (Honor Guard armor with Ultra palette and Councillor or other random helmet) was supposed to be a Zealot Elite, but is glitched up due to a programming error; it was flagged to have a "dogmatic" personality, but the level contains no data for Elites of that type.
 * Halo: Reach had the Armor hologram glitch. If you use hologram and either go into monitor mode or die, the Hologram model will be randomized, sometimes with impossible armor combos.
 * In another armor ability glitch, if the player goes into Armor Lock, switches to monitor mode, and choose to delete all of the Armor Lock items from the map, the player will have permanent Armor Lock upon returning to player mode, and it will not go away until the player dies.
 * Some enemies from the infamously glitchy Action 52 games seem to fall into this category. For example, the sprites in Level 5 of Ninja Assault are all scrambled, but appear to be birds and a rhino-type boss. Also, most of the enemies in Spread Fire. In Thrusters, your ship turns into one of these when you crash in the second level, which is Unwinnable anyways unless you have the right ROM and emulator.
 * There was a custom physics model for Marathon that turned the players weapons and the BOBs into stuff like this.
 * Tales of Destiny had such a hidden character who was Dummied Out, but still gettable because of a bug. This led to many a Mis Blamed as some fans believed he/she was edited out of the US version only, when in fact you couldn't get him/her in the Japanese version either. They merely corrected the bug in the US version.
 * One glitch in Zelda II: The Adventure of Link lets you travel to earlier dungeons, only using the graphics from later dungeons, enabling you to do things like see unused window graphics if you go from a dungeon that had no windows to one that did. However, this also results in the boss of the dungeon you're visiting being pieced together from the sprite of the boss of the dungeon you were in before, as can be seen in this video, just under six minutes into the video.
 * Kingdom of Loathing parodies this with the Bugged Bugbear monster, and later the Baby Bugged Bugbear familiar based on it. Neither is actually glitched, but both have chunks of their images replaced with ones and zeroes, and both spit out MySQL error messages with almost everything they do.
 * The Final Fantasy I Game Genie code VYUOKITE allows you to select from 244 of these at the beginning of the game. A large number of those are automatically killed when used, but a surprising number are actually usable.
 * As shown in the AVGN's Game Glitches episode, the characters in the PlayStation 2 Rocky game can glitch up and become this.


 * In City of Heroes, occasionally you will find yourself fighting someone named BOSS_NAME. They're perfectly normal bosses of the appropriate faction, in all but name.
 * Due to the way Sid Meier's Alpha Centauri loads factions, the player can load a perfectly good faction from the credits, a sound file, some graphics, or even nothing at all.
 * When PlayStation 2 emulators became almost fully functional, a lot of dummy data was found in Final Fantasy X. This included several weapons, including a buster sword, but they're very glitchy and crash the game in most cases.
 * Test Drive Unlimited has a neat looking car substituting for any corrupted car in your save file or game installation. It looks somewhat like an Alfa Brera and clearly has had a lot of work put into it for something that is only supposed to appear in case of a fatal flaw in the game.
 * The dungeon crawler game Mordor has one of these called the GOBLIE. This is a very weak companion monster that would be completely useless even if they didn't always turn up dead. It arises from a flaw in the acid spit attack that some monsters have. Occasionally an acid spitter will attempt to spit on your companions, but if your character has never had a companion then it generates a GOBLIE and immediately kills it.

Anime and Manga

 * Dennou Coil has Illegals, sentient viruses that feed on metabugs, and may or may not have been cyberpets once.
 * .hack//Sign and the first set of games had "Data Bugs." Glitched monsters (and corresponding wonky graphics) within the Virtual Reality MMORPG with infinite Hit Points who can send players into comas (not as permanently as the Phases). Only a game reprogramming device like the Twilight Bracelet can defeat them.

Film

 * Mal of Inception is an Ax Crazy Humanoid Abomination projection of Dom's guilt, who tears through the dream levels shooting people and generally fucking things up.

Web Video

 * was revealed to be the trope namer itself on Atop the Fourth Wall.