Ace of Spades
The Ace of Spades is typically used by murderers and other thugs to mark the death of one of their victims. For example, a sniper would leave this card on the corpse of the snipee to indicate that they finally shot them. Police normally intervene and pick up the Ace of Spades, giving the felon a chance to escape.
No further use for this card has been found, leading some US states to ban carrying the card in public. Anyone found carrying it is sent to prison .