Cerberus

Cerberus was the three-headed hound that guarded the gate to Hades. According to the Theogony, Hesiod said that Cerberus had fifty heads. Cerberus was the monstrous offspring of Typhon and Echidna.

Cerberus was to keep the dead or shades from returning to the world of the living, as well as preventing the living from coming into Hades.

Heracles had to bring Cerberus to the surface as the last of his labours. Hades permitted Heracles to try, but without the use of a weapon, Heracles had to wrestle and drag the hound to Eurystheus. Eurystheus fearfully told Heracles to send it back to its master.

Cerberus allowed other living people through such as Theseus and Peirithoüs, or Orpheus, and Pysche. Orpheus was allowed through because of the music he played. Psyche had to fetch the make-up box from Persephone. Cerberus allowed her to pass because Psyche gave the hound some sweet cakes.