It is found in Pokémon Yellow only - it can only be found by doing Method #3 of the Mew glitch with Pokémon with a special stat of 196. It can also be obtained if a PokéWTrainer is traded from Red and Blue.
X ゥ- xゥ, features a glitch screen, particularly the purple-tint variant.
As its primary type is one of the glitch types, which do not have any weaknesses or resistances, this glitch Pokémon has the same weaknesses and resistances as a pure Normal-type Pokémon.
As it learns the HM technique as a starting move, and cannot be traded to any game containing a Move Deleter, X ゥ- xゥ, is unable to forget Flash. However, if obtained at Level 12 or higher, or traded from Red/Blue, it will not know Flash.
Unlike many other glitch Pokémon, this Pokémon has relatively balanced stats. They are, however, much higher than non-glitch Pokémon.
This glitch Pokémon article is part of Project GlitchDex, a Bulbapedia project that aims to write comprehensive articles on glitches in the Pokémon games.