Tyrryxian

The Tyrryxians were a telepathic humanoid race. They used the mindless Mantis as workers until one of them developed free will and led his followers in stealing a spacecraft. The Tyrryxians sent their battle fleet in pursuit, but the Mantis used their size control technology to shrink their ship to avoid detection. Two Tyrryxians on the ship, who had shrunk themselves to hide from the Mantis, made contact with the Third Doctor and helped him capture the Mantis leader and destroy their vessel. (COMIC: Size Control)