This robot can swim under the sand and dig itself out too, thanks to two front limbs that mimic the oversized flippers of turtle hatchlings. It’s the only robot that is able to travel in sand at a depth of 5 inches. It can also travel at a speed of 1.2 millimeters per second–roughly 4 meters, or 13 feet, per hour. This may seem slow but is comparable to other subterranean animals like worms and clams.