Iron jaw (circus)

The Iron Jaw is a traditional aerial circus act.

The act consists of a performer raised into the air by a cable, trapeze or other similar apparatus, supported only by a bit clamped between her teeth. Depending on the apparatus the bit is attached to, the performer can alternately swing in circles around the ring below or spin wildly in place, controlling speed by alternately extending her arms and legs out or bringing them in close to her body to speed up (known as the conservation of angular momentum principle).

The act is frequently referred to as the Human Butterfly due to the removable wings which traditionally adorn the performer's costume.