University of Southern Denmark recently demonstrated a soft robot capable of navigating complex terrains using a combination of inflatable actuators and a patterned "kirigami" skin, all moving via rectilinear motion.
You probably think it looks like a worm and it can certainly go places only small things could go.
It's not very fast, only 11 millimeters per second, but it can twist, turn, and navigate through tight spots thanks to its anisotropic anchoring and flexible skin.
Credit: SDU Soft Robotics