MissingNo.

MissingNo. (けつばん Ketsuban) is a Glitch Pokémon encountered in Pokémon Red and Blue and in Pokémon Yellow. It is the most well known glitch pokemon out of all of them. Glitches that have appeared in other games have also been reffered to MissingNo. but have no relation to the original. The name has been shortened from missing number, because it was put in the game to take the places for non-existent pokemon. The reason there were non-existent pokemon was caused by how they made the games, because of this, the lowest variable possible to put on the game was 256. In the original games there were only the original 150 (with exception of Japan, which had 151) there were still about 105 - 104 slots left. And thus, all 105 slots were filled with MissingNo. or 'M.

MissingNo. has two types, one of which is not a real type and appears on only it and 'M. It is a Normal, and Bird-type Pokémon.

Appearance
MissingNo. has various forms, four of which are the most well known. One of the most common ones is a box-shaped, backwards "L", filled with a circuit-board pattern. Its other forms can be one of two fossilized Pokemon, Aerodactyl or Kabutops. This appearance comes from the fossil sprites of these two pokemon from the Pewter City Museum. It's fourth appearance is a darkly coloured ghost. This image comes from the appearance of ghost pokemon in the Pokémon Tower before you recieve the Silph Scope.

MissingNo.'s Forms
Normal Form Aerodactyl Fossil Form Kabutops Fossil Form Ghost Form
 * [[Image:MissingNo.Sprite.png]]
 * [[Image:MissingNo.(Aero)Sprite.png]]
 * [[Image:MissingNo.(Kabu)Sprite.png]]
 * [[Image:MissingNo.GhostSprite.png]]

Effects
MissingNo. effects can range from minimal visual effects to minor damage to game data. Most of the glitches involve some of the game's visuals including the player's image and sprite, Pokédex entries, on-hand Pokémon and others. When this happens the image becomes scrambled, somewhat like MissingNo.'s normal appearance. Besides graphical glitches, MissingNo. can scramble a Hall of Fame record if caught after a player has the record. The damage is not major but it will be permanent.

Reason
Missingno is the Glitch Pokémon that appears after viewing the Old Man's tutorial in Viridian City on how to catch Pokémon, then immediately Flying to Cinnabar Island and Surfing along the right hand side of the island, near the Gym, until one is encountered.

When you talk to the old man in Viridian City, the game needs to change the player's name to "OLD MAN" so that it will display the "OLD MAN" sprite instead of the original character. Because of this, the programmers needed a place to store the player's information and name while the "OLD MAN" data replaced it, so they decided to store it in the area where wild Pokémon information is. This was done because of the lack of memory on an original Game Boy. This normally wouldn't cause any glitches because the correct data for wild Pokémon available is written to this area in memory whenever the player travels to an area where it is possible to catch wild Pokémon.

Cinnabar Island's coast has no data for indicating which wild Pokémon are available because no pokemon can be caught in the general area. The same is true for both Viridian City and Cinnabar Island itself. The game uses whatever data was already in the nearby area, or whatever area the player was in last, when determining which wild Pokémon are encountered and what their levels are. This is seen when exiting the Safari Zone and flying directly to a place with no available pokemon memory such as Cinnibar Island. When this is done, Safari Zone Pokemon can be encountered along the right side of the island because Cinnibar Island is using the Safari Zone's available Pokémon data.

Normally this memory space ,found on the side of Cinnibar Island, would hold the data of the last area visited where wild Pokémon were catchable and their level data. But since the player's last visited area had no Pokémon and instead the player's temporarily stored name (Viridian City), this leaves the game placing in the temporarily stored data in the available Pokémon data's place. This is what causes Missingno's. availability.

The name of the player has much to do with the level and appearance of MissingNo.. As stated earlier, MissingNo. appears due to a lack of Pokemon data in Cinnibar and the use of the player's info (which has been stored in the pokemon info data in Viridian City) inserted into this empty space. The type of Pokémon or MissingNo. the player encounters is determined by the characters used in the 3rd, 5th, and 7th characters of the player's name. The level of the Pokémon or MissingNo. is based on the 2nd, 4th, and 6th characters.

Other Glitches
Even after Pokémon Red and Blue and Pokémon Yellow, glitches appeared in later games and are often called MissingNo., though these are not the original MissingNo., they are other MissingNo.-type glitches that are usually called Glitch Pokémon.

Besides MissingNo., there are literally hundreds of other Glitch Pokémon, some more well known then others. Others include 'M, h POKé, Charizard 'M, and LM4. Most of these are obtainable by use of the Mew Glitch.

When Pokémon Ruby, Sapphire and Emerald were created, another Glitch Pokémon was found, but the glitch in the Generation III games shows a black circle with a question mark in the middle. Another glitch, in the same games, shows an image two question marks. These Glitch Pokémon forms are obtainable when using roms, cheat codes and hacking devices. These glitches are labled as ?|?????????? and ?, known also as Decamark.

Another Glitch Pokémon, in Pokémon Diamond and Pearl games, with similar features as MissingNo. is the DPBox, sometimes called the "Diamond and Pearl MissingNo.". DPBox shares a similar appearance to MissingNo in that it is a large, blocky figure. While not causing any graphic scrambles, DPBox does have some abnormal effects such as cloning items.