Ghostrick Mary (LVAL-EN022) - Legacy of the Valiant Unlimited

Cannot be Normal Summoned, unless you control a "Ghostrick" monster. Once per turn: You can change this card to face-down Defense Position. When you take damage: You can discard this card; Special Summon 1 "Ghostrick" monster from your Deck in face-down Defense Position. You can only use this effect of "Ghostrick Mary" once per turn.