Last Laugh is Mark Elsdon’s brilliantly clever take on the “stranger card” plot.
Two decks of cards are introduced, both with different backs. One of the decks is removed from its box, shown to be 100% regular and shuffled. Your spectator now selects a card from the deck (sight unseen) and places it in his pocket.
You now state you are going to attempt to cut to the matching card but from the other deck.