Perish Song

Every Pokémon is given a counter that starts at 3 and decreases by 1 at the end of every turn, including this one. When a Pokémon’s counter reaches zero, that Pokémon faints. A Pokémon that leaves the field will lose its counter; its replacement does not inherit the effect, and other Pokémon’s counters remain. This effect is passed on by Baton Pass. This move cannot be copied by Mirror Move.

“Any Pokémon that hears this song faints in three turns, unless it switches out of battle.”