The Pokémon switch message glitch occurs in Pokémon Red, Blue, and Yellow, Pokémon Gold, Silver and Crystal and was documented by glitcher Crystal_.
When the player switches out a Pokémon from battle, a message will be displayed depending on the amount of HP that the opponent had lost, as such:
|(last switch-in enemy HP-current enemy HP)
|HP stayed the same.
||"(POKéMON), that's enough! Come back!"
|HP went down 29% or less.
||"(POKéMON), come back!"
|HP went down 30-69%.
||"(POKéMON), OK! Come back!"
|HP went down 70% or more.
||"(POKéMON), good! Come back!"
The developers apparently didn't account for cases where the enemy's HP from the previous switch is less than the enemy's HP on the current switch. This means that if the enemy Pokémon recovers HP and ends up with more HP than it had before, switching will still bring up any one of the above messages, most commonly the message "(POKéMON), good! Come back!".[clarification needed]