Minotaur

The Minotaur was a creature from Greek mythology. It was said to have the head of a bull and the body of a man.

The Third Doctor learned that the Minotaur was real during a trip to Atlantis. The creature was formerly a member of Dalios's court, a great athlete who desired the strength of a bull and a long life in which to use it. Kronos granted him his wish, and the creature was made guardian of the Crystal of Kronos until the Doctor defeated it. It likely died when Atlantis was destroyed by Kronos.

_{Biography from the TARDIS Data Core article, licensed under CC-BY-SA}