Error traps and anti-cheating traps

An error trap or error trapper is an informal term for events or instances game developers, or hardware developers incorporate into their software or hardware to avoid the effects of any glitches, or undesirable results which result in such an error. Common examples of error trappers include the infamous "This program has caused an illegal operation" message in computer software by Microsoft prior to Windows XP, or many messages used by games to explain that the game save file is unreadable.

In the Pokémon games, as well as serving the purpose to deter glitches, error trappers may also be used to discourage players from cheating. Such examples include the "This Pokémon is illegal" message from Pokémon Colosseum, or theoretically Pokémon named "Bad EGG", which can appear when the respective Pokémon has a total amount of EVs higher than 510 from Pokémon games from and after Generation III.