Sky Guardian Supreme Dragon, Impede Dragon

-Opponent Turn's Guard Step-[Choose a card with " Heal" from your hand, and discard it] Call this card to your from face down. :When placed on , [choose a face down from your G zone, and turn it face up], your opponent chooses one of his or her rear-guards, retires it, binds it face up, and if the number of your rear-guards is less than your opponent's rear-guards by two or more, your opponent chooses one of his or her rear-guards, and retires it.