Glitch Unown

Glitch Unown (Japanese: バグアンノーン Bug Unknown) are invalid Unown in the Unown Mode in Generation II. The term is also used to refer to a class of glitch Pokémon with index values greater than 684 in the main-series Generation V games.

Causes
Normally the Unown Mode should display an entry for each Unown. This limits the valid values to 26, while there are 256 possible values. For this reason there are 230 hexadecimal values in the Unown Mode where the data does not consist of a valid Unown's picture and name. Index numbers past 26 presumably represent unrelated data encoded as "Unown" data.

Registering glitch Unown
To register a glitch Unown in the Unown Mode, the player may obtain a ????? (Hex FF) as a bad clone from the Celebi Egg glitch. If the ????? is placed as the first Pokémon in the party, the player can use the "MOVE W/O MAIL" option to withdraw over 6 Pokémon.

This corrupts RAM data located past the expected end of the Pokémon data structure, although there are only a limited amount of Pokémon that the player can withdraw before the game freezes.

If details about a 'post-6' Pokémon conflicts with data about Pokémon in the Unown Mode, then it is possible to replace entries with glitch Unown, provided that the player already has the Unown Mode, for example the index number of the current fourth move's PP of Pokémon #11 conflicts with RAM data associated with the first Unown.

It is possible to replace the first Unown with a glitch Unown this way provided that the player used PP Ups to raise its associated index number past 26.

In the process of obtaining glitch Unown, the player will be corrupting the values of other RAM addresses such as those determining seen or owned Pokémon in the Pokédex, or the number of options on the menu.

Types

 * Static: the glitch Unown takes its data from an address in the game's RAM which is not related to the player's location. As result, the glitch Unown has a unique sprite.
 * Dynamic: the glitch Unown takes its data even partially from the player's location. The glitch Unown will change its sprite depending on where the Unown Mode is displayed.
 * Influenced by the Pokédex Mode: by changing the Pokédex Mode the glitch Unown will change.

Forms

 * Letters: the glitch Unown is composed of Unown's letters on a black background.
 * Lines and/or squares: the glitch Unown is made up of black lines or of black/white squares.
 * Mixed: means that the glitch Unown is made up of symbols and/or of scrambled Pokémon pictures.
 * Unknown: some glitch Unown can't have their description shown because they freeze the game when accessed.

Effects
A glitch Unown can trigger several other glitches when displayed, including corruption of the Pokédex, corrupted graphics, the Trainer House glitch, corruption of the saved file, and/or the glitch dimension effect. The message "No windows available for popping" may also appear. Glitch messages, which will be placed directly in the player's mailbox (listed below), may appear as well.

List of glitch Unown which cause glitch messages
This is a list of glitch Unown that change the values associated to the player's mailbox, with the exact amount of glitch messages that will be added. Missing hexadecimal values will not corrupt the player's mailbox.

Generation V Glitch Unown
Some Pokémon with an index value of greater than the largest valid index number in that game (684 in B2W2) can also be referred to as "glitch Unown". These glitch Pokémon use the sprites of Unown, alongside the cry of a. Their names consist mostly of question marks (sometimes incorporating kanji and even Korean hangul in B2W2), and their match those of alternate forms of Pokémon like, , , and. It may be the case that, like Generation III, only the sprites are given these index number, and all information is instead pulled from the true Unown index number, leaving these other values to be filled in with either garbage data, or the data corresponding to other Pokémon forms which may be stored here instead.

Video
Unown Glitch