The folding coin (AKA Coin in the Bottle) is one of the most amazing coin effects. Many professional performers have used this effect in their act. You borrow a quarter and an empty bottle. While the spectator is holding the bottle, you apparently knock the borrowed coin through the bottom of the bottle. After everyone has confirmed that the coin is actually inside the bottle you shake the coin out through the neck which would be impossible because the neck is smaller than the coin. Complete with coin and instructions.