Cerberus

Cerberus, in Greek Mythology, the many-headed dog—according to Hesiod, the offspring of Typhaon and Echidna—who guarded the portal of the infernal regions. Later writers describe him as only three-headed, with the tail and mane composed of serpents, though the poets sometimes encumber him with a hundred heads. Orpheus charmed him by the magic of his lyre, and Hercules overcame him by strength and dragged him to the upper world.