Ghostrick Fairy (IGAS-EN023) - Ignition Assault 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 this card is flipped face-up: You can target 1 "Ghostrick" card in your GY; Set that card (but banish it when it leaves the field), then, you can change face-up monsters your opponent controls to face-down Defense Position, up to the number of Set cards you control.