Metamorphosis is one of the most famous stage illusions. It begins with the magician and assistant producing a large trunk. The trunk is shown inside and out and may be examined by the audience. Next is shown a burlap bag large enough to hold a full-grown adult. The bag is shown inside and out and may be examined by the audience. A pair of handcuffs is introduced next. These may be shown inside and out and be examined by the audience. Finally, the cover is removed from a table on which are various chains, locks, shackles, and other items needed for the routine. Everything on the table is shown inside and out and can be examined by the audience
The assistant handcuffs the magician. The handcuffs are shown to be locked. The magician's ankles are shackled next, after which the keys to the handcuffs and shackles are thrown into the audience. A roll of duct tape from the equipment table is used to wrap the restraints, further bind the magician's arms and legs, and cover the mouth so that breathing is difficult and screams are impossible. The magician's assistant lifts the magician into the burlap bag, closes its top, and sews it shut with a portable industrial sewing machine. The magician is placed in the trunk, which is closed, locked, wrapped in chains, and (in some variations) welded shut.
With everything in place and the magician seemingly unable to escape, the assistant picks up a large curtain rod with a large curtain hanging from it and climbs on top of the trunk. The curtain is held to obscure the trunk from the audience. The assistant then counts, "One! Two! Three!" and on the count of three lifts the curtain so that for a moment nobody is visible and then drops it to reveal, not herself, but the magician! The assistant has disappeared completely.
Harry Houdini himself invented metamorphosis. Originally, he performed it his wife being bound and placed in the trunk, not he. At one time, Houdini even tried adding to the impossibility of the effect by filling the trunk with concrete after his shackled wife got into it, but that did not work out as planned. Houdini's second wife came up with the idea of having the trunk pushed off a bridge and into a river once she was inside, but this high-publicity version also didn't work out. With his third wife, Houdini decided to start playing things safe -- he kept things simple (as described above) and changed the routine so that it was the magician who made the initial escape.
The first versions of Metamorphosis required great skill and timing on the part of the person put in the trunk, who had to work their way out of all manner of restraints. But in the final version, in which it is the magician who is bound, no escape is necessary. This is because the magician never really gets into the trunk.
The person who is handcuffed, etc., is a double for the magician, hired from a local talent agency, sworn to secrecy, and prepared by an expert makeup artist. The assistant who binds the "magician" is not the magician's assistant at all, but the magician himself, wearing a latex mask and break-away clothing. After the double is sealed in the trunk, the magician gets on top of it, counts to three, raises the curtain with one hand and rips off the mask and clothing with the other. The costume is thrown to the floor, the curtain is thrown on top of it, and the magician appears to have escaped from the trunk!
The double can be extracted from the trunk at the magician's leisure after the show, or, if the schedule is really tight, at a later date.