You display a small block with a picture of Houdini on it and place it in a clear tube. You then pour water into the tube, until Houdini is totally submerged. The tube is covered with a borrowed handkerchief.  After a few magic words the handkerchief is removed and Houdini has magically disappeared! He then appears from inside your pocket. The Apparatus stands roughly 12 inches high.

Houdini Water Escape (watch video)