Overlay Booster

If you control a monster with 2000 or more ATK, you can Special Summon this card (from your hand) in face-up Defense Position. You can only Special Summon "Overlay Booster" once per turn this way. During your turn, except the turn this card was sent to the Graveyard: You can banish this card from your Graveyard, then target 1 face-up Xyz Monster you control that has Xyz Material; it gains 500 ATK for each Xyz Material attached to it.