In rummy, the Joker is a card that can be used as a trump card. It can be used in place of any missing card to form a set or sequence. There are two types of Jokers: printed Jokers and wild cards. While printed Jokers come with a joker’s picture printed on them, wild cards are chosen randomly at the beginning of each game. Wild cards also act as Jokers, so they are a kind of additional Jokers.