A playing card visibly stretches longer right before your spectators' eyes, and you never touch it with anything but your hands.
Here's the plot: a spectator selects a card from a normal deck. You reach into your pocket and pull out your prediction, but they insist you've got the wrong card. That's when things get interesting. The card in your hand slowly grows, stretching impossibly long to reveal all eight hearts. It's a baffling moment that plays big even for small audiences.
The gimmick handles the mechanics, so you can put your energy into your presentation and enjoy the reactions.
