You don't have to be double jointed to shock your audience with this unforgettable effect. Place your hand on a table, and ask a spectator to follow along with your movements. They will freak out when you suddenly twist your arm around in an impossible way they cannot repeat. Your spectator will be way too involved playing along that they will never figure out the method. Everyone will start to question what other crazy tricks you can do with your arms next. This can be performed to great comedic effect for both close-up and stage shows.