A selected member of the audience presses a large button in front of the stage.This charges up a platform and, a couple of seconds later, it gives the magician a kick into the air, making it look like he has jumped up really high.
At the apex of the jump trajectory, the magician waves his wand and sparkles and stars issue forth from it in the direction of a coat hanger, to the extreme edge of the stage.
A T-shirt slowly materialises on the coat hanger, swinging from side to side.
The audience member gets onto stage, picks up the T-shirt, and shows it to the audience to prove that it's real. They get to take it home with them.
A special pheromone has been sprayed onto the T-shirt that makes it irresistible to wear.
Two days after the performance, the audience member will still be wearing the T-shirt. At the same time in the evening as the act was, it will dematerialise, leaving the audience member topless.
The clever bit is that, during the wearing time, the T-shirt will have stored up some of the heat energy generated by the person. When it gets re-materialised back onto the coat hanger, it wirelessly transmits the stored energy to a battery under the platform for the performance after the current one. In this way, this trick becomes the first illusion to be given the coveted "A" energy rating.
I might make a flash to explain this in more detail for when I submit it to the trick approvals department.
