"Spot", a quadruped prototype robot, walks down a hill during a demonstration at Marine Corps Base Quantico, Va.,Sept. 16, 2015. Employees of the Defense Advanced Research Projects Agency trained Marines from the Marine Corps Warfighting Lab how to operate “Spot”. - "Spot", a quadruped prototype robot, walks down a hill during a demonstration at Marine Corps Base Quantico, Va.,Sept. 16, 2015. Employees of the Defense Advanced Research Projects Agency trained Marines from the Marine Corps Warfighting Lab how to operate “Spot”.