Karadax (planet)

Karadax was a planet inhabited by a bipedal shark species, also called the Karadax. During the Tenth Doctor and Martha's visit to Karadax, the Doctor fought a Karadax drone, while Martha met an android and a Karadax from the future who had come back in time to kill her, because without her the Doctor would be unable to stop their future plans. He failed, and the Doctor decided to check up on Karadax every few hundred years. (PROSE: Rewriting History)