Star-vader, Cold Death Dragon

: 1 When this unit is placed on , if you have a Link Joker vanguard, and your opponent has a locked card, you may pay the cost. If you do, your opponent chooses one of his or her , and put the top card of his or her deck into that face down as a locked card. (The locked card is turned face down, and cannot do anything. It turns face up at end of the owner's turn.)