The movement-creating device is called a "hydraulically amplified self-healing electrostatic" actuator. That's a HASEL (pronounced "hey-zuhl") actuator or muscle, for short. The pump-free devices are pouches made of the same inexpensive plastic that makes up potato chip bags and filled with an electrically insulated liquid, similar to canola oil. The devices change shape when voltage is run through them, and the malleable oil gives the mechanism the potential to self-heal. "You can control it with only two wires," Science paper lead author Eric Acome says, referring to the wires used to power the electrodes. "We don't need to have some...