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. (PROSE: A History of Humankind)

Legend
In legend, the minotaur was imprisoned by King Minos of Crete in the middle of a huge specially designed maze built at Knossos, which was called the Labyrinth. Forced to pay tribute to Minos, Athens sent seven young men and seven young women every nine years to be devoured by the Minotaur. The Athenian prince Theseus insisted on going as one of the men, and helped by Ariadne - the daughter of King Minos - he slew the Minotaur. (PROSE: A History of Humankind) The Fourth Doctor claimed to have given Theseus the ball of string that he used to find his way around the labyrinth in which the Minotaur resided. (TV: The Creature from the Pit)

Encounters with minotaurs
The Second Doctor and Zoe Heriot encountered the Minotaur in the Land of Fiction. It vanished when they denied its existence. (TV: The Mind Robber)

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. (TV: The Time Monster)

The Greek hero Theseus was renowned for fighting the Minotaur. The Eighth Doctor, Charley Pollard and C'rizz encountered an illusory Minotaur on Caerdroia. (AUDIO: Caerdroia)

Extraterrestrial life forms which resembled the Minotaur included the Nimons, a related species called the Minotaurs who were the Nimons' "distant cousins", the Tauride and Taureau's race. (TV: The Horns of Nimon, The God Complex, COMIC: Minor Trouble, COMIC: The Forgotten) A member of one of these species (or perhaps a different species) tended bar at Korova Moo. (COMIC: Agent Provocateur)