Metamorphosis (illusion)

Metamorphosis is the name of a stage illusion invented by John Nevil Maskelyne, but most often associated with famous magician and escape artist Harry Houdini, and performed to some renown (for speed) by The Pendragons, among many others.

In the illusion, an assistant (Houdini employed his wife Bess) is locked inside a large box or trunk, often after being restrained with handcuffs, ropes, bags, etc. The magician stands upon the trunk and holds a curtain up to momentarily conceal his entire body. When the curtain is lowered, it is revealed to now be the assistant standing atop the box, the magician and assistant having changed places instantaneously. When the box is opened, it is shown to contain the assistant, restrained as the magician had been.

Variations include the Aquarian Illusion performed by Mark Wilson, wherein a tank filled with water is used and a woman assistant is locked inside underwater, and Penn and Teller performing the illusion underwater with the woman assistant handcuffed & locked in a steel cage. Each adds an exciting element of danger and peril - If anything goes wrong, the beautiful young lady will drown!