:When this unit is placed on , if your opponent's vanguard is grade 3 or greater, COST [ a unit with "Marco" in its card name], your opponent chooses up to one card from their hand or rear-guards, they discard if a card was chosen from hand, and retire if a rear-guard was chosen. If no opponent's cards were put into their drop, choose one of your opponent's vanguards, and deal one damage.