We've seen all kinds of crazy jumping robots, from humanoids to grasshoppers to soft and flexible spheres. But when you start making small robots, like seriously small robots (on the millimeter scale), you have to find new ways to get them to jump, and the Army Research Laboratory has teamed up with the University of Maryland to develop a couple clever ideas. Pictured above is a four millimeter-long robot, complete with a power source, an integrated control system, and light sensors. To move, it relies on on the rapid conversion of stored chemical energy to gas in a chemical reaction, which is just a fancy way of saying either "rocket motor" or "controlled explosion." Underneath the robot is a small chip of nanoporous silicon that gets infused with a sodium perchlorate oxidizer, and when a current heats up the chip, it ignites, propelling the robot upward.