Most robotic materials and prosthetic limbs are constructed out of rigid materials that don’t allow for flexibility. But the HASEL muscle is created from plastic pouches, filled with an electrically insulated oil. The pouches are made of the same cheap material used in potato chip bags. When electrified, the liquid inside changes the shape of the muscle, simulating movement that is flexible yet strong. The hope is to create more human-like movements in robots, which could help in prosthetics and industrial applications.