Krikkitman

The Krikkitmen were androids from the planet Krikkit. Approximately 5,000,020 of them were made.

History
A dust cloud separated them from the rest of the universe, so the Krikkitas thought that they were the only beings in the universe. After learning that they weren't (when a spaceship crashed on their planet), they set out to destroy the universe. They created androids and made ships and sent them off as perfect killing machines. It turned out that this was a ploy by a bored supercomputer, Hactar. After the Krikkit Wars, the Time Lords stored the Krikkitmen in their own dimension on Shada. A rogue Krikkitman later freed them and set out to continue their goal, but the Fourth Doctor and Romana prevented this. They did so by tricking the Krikkitmen into turning themselves on and off repeatedly until they exploded. (PROSE: Doctor Who and the Krikkitmen)