Pfc. Marcus Beedle looks over his shoulder at the robot following him. The machine's four legs are eagerly stamping the grass, its sensor-laden head held high. "LS3, follow tight," Beedle says to the robot, and the Legged Squad Support System—which stands taller than a dog but smaller than a mule—follows in the exact footsteps of its Marine Corps handler. ... The LS3 is made for war zones, but it is not viewed as a weapon. It's a mule—though some Marines would like to see a little more. "We'd love a machine gun on it," says 1st Lt. Alex Hurran.