The magician walks behind a spectator while the spectator pulls up shirt or blouse to reveal belly. The magician then pushes an arm through the spectator’s back until it bursts through the skin of the spectator’s belly. Spectators scream. Parents cry. Surgeons envision a lucrative reconstruction opportunity.
As with most good illusions, the secret is a simple one. It is impossible to put your arm through someone else’s torso without great inconvenience and mess, so the magician does not even try. Instead, slight of hand is used to replace the spectator’s torso with a false one made of paper maché that can be easily punctured. What remains is acting.