The inverse sprites glitch, also known as inverted sprites or flipped sprites is a glitch effect in Pokémon Red, Blue, and Yellow. It causes the battle/status sprites of Pokémon, Trainers, as well as the player character to become roughly flipped.
The glitch will also corrupt the player character's Trainer Card profile sprite, revealing a fragmented mess of the player sprite and his badges.
The effect is usually caused by viewing the front sprite or summary of specific glitch Pokémon. Glitch Pokémon which qualify as having 'good' sprites in this case (including hybrid glitch Pokémon) do not cause the glitch.
The inverse sprites glitch may also be caused by encountering certain glitch Trainers, with both the Trainer class and roster as combined factors influencing whether the glitch occurs.
Address 0xD0AA in Pokémon Red and Blue (0xD0A9 in Pokémon Yellow) controls whether the 'flipped sprites' effect applies to Pokémon, with values other than 0x00 causing the sprite to become flipped or the inverse sprites glitch to occur.
More research is needed for this article.
Reason given: Elaborate why these are corrupted
While the inverse sprites glitch seems to mainly only affect the visuals of the game, it does have a use for move 0x00 corruption. Specifically, if the last time the Pokémon menu was opened was within battle, then performing one of these corruptions (for English games, another language game may give different results) will provide either a Level 127 MissingNo. (of the hex:32 variant) if the inverse sprites glitch effect was inactive before opening the menu, or a Level 127 Horsea if the effect was active at that time.