Cerberus is the monstrous hound that guards the gates of the underworld, permitting the dead to enter but none to leave. Born to the monster-pair Typhon and Echidna alongside siblings like the Hydra, the Chimera, and the hound Orthus, he is usually pictured with three heads and a serpent for a tail, though Hesiod’s earlier account gives him fifty. He answers only to Hades, and the living who wish to pass him alive — Orpheus charming him with music to retrieve Eurydice, the Sibyl drugging him with a honeyed cake to lead Aeneas through, Psyche doing the same on Cupid’s errand — must trick or lull him rather than fight him.
His most famous appearance is as Heracles’s twelfth and final labor, sent by King Eurystheus to fetch the hound up from the underworld with bare hands and no weapon. Heracles wrestles him into submission, drags him to the surface at Eurystheus’s court and terrifies the king so badly that he hides in a storage jar, before Heracles returns Cerberus safely to his post below.
Κέρβερον ὠμηστήν, Ἀίδεω κύνα χαλκεόφωνον, πεντηκοντακέφαλον, ἀναιδέα τε κρατερόν τε
“Cerberus who eats raw flesh, the brazen-voiced hound of Hades, fifty-headed, relentless and strong.” — Hesiod, Theogony