The tiniest robot in the world is smaller than a flea, shaped like a cute little crab, and can jump, walk, and turn on command. Engineers at Northwestern University developed the robot using an alloy that remembers its shape; when it’s heated up by a precision laser at specific points, the alloy flexes, and when it cools, it pops back to its original form. This rapid heating and cooling is what moves the robot arounds, at speeds up to half their body length per second. The study was published Wednesday in the journal Science Robotics.John A. Rogers, the lead engineer for the study, said in a press release he imagines these tiny crabs going into delicate surgical situations like unclogging arteries, or excising cancerous tumors. Outside of our bodies, he could see them working in machines or repairing small structures. The tiny size of these robots makes them cool—and move—faster than they would if they were larger. But their form, modeled after “peekytoe” crabs, a type of sand crab that scuttles along beaches, doesn’t have a purpose beyond whimsy, according to the researchers. “With these assembly techniques and materials concepts, we can build walking robots with almost any sizes or 3D shapes,” Rogers said. “But the students felt inspired and amused by the sideways crawling motions of tiny crabs. It was a creative whim.”