Origami Action

Origami doesn't just cover still-lifes; origami can move in clever ways. Action origami includes origami that flies, requires inflation to complete, or, when complete, utilizes the kinetic energy of your hands applied at a certain region on the model and transfers it through an internal mechanism to move another flap or limb. Strictly speaking only the latter is really "recognized" as action origami. Action origami, first appearing with the traditional Japanese flapping bird, is quite common with Robert Lang's instrumentalists; when the figures' heads are pulled away from their bodies, their hands will move, resembling to play music.

From : Wikipedia