This Game Pak is designed only for use on the Game Boy Color.
?????????? | ????? | ! | Abnormal Pokémon | Bad Egg | Enigma Berry (Generation III) | Error! | Error codes (Generations I and II) | Error traps for damaged save data | Error traps to prevent impossible progress | Event data debugging messages | Instant victory effect (Generation II) | Mystery Zone | N/A | Pokégear instruction booklet trap | Rhydon trap | Special (location) | This Game Pak is designed only for use on the Game Boy Color. | This Pokémon cannot be traded.
The message "This Game Pak is designed only for use on the Game Boy Color." is an error trap which exists in various GameBoy Color games, including Pokémon Crystal. Its purpose, is to prevent players from playing Pokémon Crystal or another game on the original GameBoy, or Super Gameboy if it is incompatible with it. As a result, this error trap successfully blocks any game freezes or glitchy effects which may happen from doing so. This message might also exist to stop piracy, however this is uncomfirmed.
Many glitches which would usually cause a Glitch Dimension on Pokémon Gold and Silver, will instead display the "This Game Pak is designed only for use on the Game Boy Color." message in Pokémon Crystal because when the game resets due to a Glitch Dimension, it fails to check what console the player is using, and presumes that he or she is using the original GameBoy.