A bug is a restricted wildcard. In games which use a bug the jokers are added to the deck and a player with the joker can use it as a very specific type of card in their hand. There are no universal rules regarding the use of a bug and the specific rules of the game must be consulted.

In draw poker, and sort of the most common rules, a bug which can be played as an ace or as a card to complete a straight or flush. It may not be used as any other card.