In Greek mythology, what creature did Theseus defeat inside the Labyrinth?

In Greek mythology, Theseus defeated the Minotaur inside the Labyrinth.

The Minotaur was a hybrid creature with the body of a human and the head of a bull. King Minos commissioned the Labyrinth to contain it, and the structure became the destination for the Athenian tribute sent to Crete.

Theseus entered the maze as a volunteer among the Athenian youths. Ariadne provided assistance that allowed him to find his way back after the encounter. Theseus then killed the Minotaur and escaped from Crete.

The Minotaur is distinct from other Greek monsters such as the Hydra, Sphinx, and Chimera. Those creatures have different bodies, stories, and heroic opponents. The Minotaur’s defining setting is the Labyrinth at Knossos, although myth and archaeology should not be treated as identical evidence.