The motor comprises of a cubic neodymium permanent magnet and a set of four magnetic coils. These generate magnetic fields that can be turned off and on at 15Hz causing the magnet to oscillate, as the magnet is attached to the body of the robot it also oscillates. As this happens, the front and back legs of the robot alternately contact the ground, and the asymmetry of the design combined with the intentionally off-center balance point causes the robot to walk forward.
The other advantages of using a folded robot instead of just a magnet include the ability to float, as well as the ability to more efficiently perform tasks like moving objects or digging.
Once it has served its purpose, you can put the robot into a vessel of acetone and it will entirely dissolve, except for the magnet. The MIT researchers claim this is the first time that a robot has been able to demonstrate a complete life cycle.