Theseus killed bulls and villains, kidnapped women, instituted customs as king of Athens, got stuck in the Underworld, and may have been one of the Argonauts.
Theseus and the Minotaur 6th Century B.C. black figure
Public Domain. Courtesy of Wikipedia.
Theseus killed more than one bull. In this picture, he is fighting with the Minotaur, the half-man half-bull son of King Minos' wife Pasiphae.