Ghostrick Warwolf [PRIO-EN023] Common

Cannot be Normal Summoned, unless you control a "Ghostrick" monster. Once per turn: You can change this card to face-down Defense Position. When this card is flipped face-up: Inflict 100 damage to your opponent for each Set card on the field. You can only use this effect of "Ghostrick Warwolf" once per turn.