Ring of Destruction (MIL1-EN023) [Millennium Pack]

During your opponent's turn: Target 1 face-up monster your opponent controls whose ATK is less than or equal to their LP; destroy that face-up monster, and if you do, take damage equal to its original ATK, then inflict damage to your opponent equal to the damage you took. You can only activate 1 "Ring of Destruction" per turn.