EffectA woman lies down on a bench. A volunteer grabs the woman's ankles, and another volunteer grabs the woman's wrists. As the volunteers pull, the magician prods the woman's stomach. Suddenly, the woman's upper body separates from her legs. The upper body screams and goes "running" off on its arms, and the lower body stands and runs away (without screaming).
Believe it or not, the magician does not really pull anyone in half. Instead, the woman is wearing a special outfit that makes the effect possible.
The woman's "legs" are really a standard pair of high-tech bionic remote-control limbs that use the same balancing technology found in a Segway and are dressed in a simple but tasteful skirt. The woman's real legs are ensconced in a pair of tights completely covered with reflective tiles.
When the magician pretends to pull the two halves of the woman apart, the woman's real legs are extracted from a special pocket behind the robotic ones, but because they are covered in mirrors they reflect their surroundings, rendering them effectively invisible. The woman drags herself away by her arms, letting her "invisible" legs trail behind her. Meanwhile, a secret assistant high above in a hot-air balloon uses radio control to make the legs get up and run away.
Note: If you already have a pair of robotic legs, this simple effect can be constructed for about $15. If you need to purchase the legs as well, you can get a do-it-yourself self-balancing mobile radio-controlled bionic human legs kit from Radio Shack, and the total cost goes up to about $250,015.