Skovox Blitzer

A Skovox Blitzer was a robot built for war, said to be among the most dangerous weapons ever created. A single Blitzer contained enough armament to destroy a planet. One came to Earth in the early 21st century and was deactivated by the Twelfth Doctor, who developed a device that would mimic the robot's orders. He left it drifting in space. (TV: The Caretaker)