The creature had the head and tail of a bull on the body of a man.

Before he ascended the throne of Crete, Minos struggled with his brothers for the right to rule. Minos prayed to Poseidon to send him a snow-white bull, as a sign of approval by the gods for his reign. He promised to sacrifice the bull as an offering, and as a symbol of subservience. A beautiful white bull rose from the sea, but when Minos saw it, he coveted it for himself. He assumed that Poseidon would not mind, so he kept it and sacrificed the best specimen from his herd instead.

Daedalus presents the artificial cow to Pasiphaƫ: Roman fresco in the House of the Vettii, Pompeii, 1st century CE.
When Poseidon learned about the deceit, he made Pasipha, Minos' wife, fall madly in love with the bull. She had Daedalus, the famous architect, make a wooden cow for her. Pasipha climbed into the decoy and fooled the white bull. The offspring of their lovemaking was a monster called the Minotaur.