Wind-Up Zenmaister (Rare)

2 Level 4 monsters This card gains 300 ATK for each Xyz Material attached to this card. Once per turn: You can detach 1 Xyz Material from this card to target 1 face-up monster you control, change that face-up monster to face-down Defense Position, and if you do, during the End Phase of this turn, change it to face-up Attack Position.