Top 10 Mythological Creatures
This is the three-headed dog that is said to guard the underworld and prevents those who have already crossed the River Styx from ever escaping.
Capturing this hound was the final task given to Heracles. First, he had to learn how to enter and exit the Underworld alive. Hades said Heracles could bring Cerberus to the surface if he could overpower it without weapons.