A fun and baffling effect with a kicker ending that will leave them dazed and confused.
Imagine taking four face-down cards from a deck, stating is an unfinished poker hand, and then showing the rest as a mix of red and blue backs. The spectator has free choice of the fifth card for the poker hand and manages to pick an Ace to complete a Royal Flush! But the spectator counters that all the cards must be the same. The magician obliges, showing all the cards are indeed the same--BLANK!
A true baffler that will leave them scratching their heads. They'll never play poker with you again!