Stanley (Stanley)

From Tardis Wiki, the free Doctor Who reference

"Stanley" was supposedly a fifty-year-old purple cod fish on display at the London Zoo. He was actually General Secretary Muirgen Epinephelus III of the Black-fin Army of Halemida. He was a dictator responsible for the torture and murder of several millions. He was exiled to Earth, with his life prolonged by at least twenty centuries, according to the Fourth Doctor.

The Doctor and Leela visited the zoo at the time that Stanley had freed all the zoo animals. He controlled the animals, causing the deaths of several humans and other animals. He entered the Doctor's mind and learned that his planet no longer existed. He then used a boy and a monkey to help him commit suicide. (PROSE: Stanley)