Star-vader, Mulepton

:[ 2-cards with "Star-vader" in its card name] When this unit is placed on , if you have a vanguard with "Star-vader" in its card name, and your opponent has a locked card, you may pay the cost. If you do, choose up to one of your opponent's open , your opponent chooses a card from his or her hand, and puts it on that face down as a locked card.