If the user is not a Ghost type: Attack and Defense increase by one stage; Speed decreases by one stage. If the user is a Ghost type: Sacrifices 50% of their maximum HP and lays a Curse on the target. Cursed targets lose 1/4 of their maximum HP at the end of every turn. A Ghost type can self-KO with this move.
This move is actually the ??? type, but for the sake of simplicity, it is listed as Ghost here.