Cerberus
in Greek mythology, the three-headed dog that guards the underworld
In Greek mythology, Cerberus (Greek: Κέρβερος, Kérberos; Latin: Cerberus) is the monstrous, multi-headed dog that guards the entrance to the Underworld, preventing the souls of the dead from leaving.

Often called the "hound of Hades", Cerberus was one of the numerous offspring of the monsters Typhon and Echidna; he is usually depicted as having three heads, along with a serpent for a tail. Cerberus is primarily known for being captured by Herakles, as the last of the hero's Twelve Labors.
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