In Greek mythology, the creature that guards the entrance to the Underworld is known as Cerberus. This three-headed dog is tasked with preventing the souls of the dead from escaping Hell and keeping intruders away. Each of Cerberus’s heads serves a different purpose, symbolizing the past, present, and future. As a fearsome guardian, Cerberus is often depicted with a serpent's tail and a fierce demeanor, reinforcing his role as a protector of the afterlife. Myths involving Cerberus often highlight his encounters with heroes, such as Heracles, who famously captured him during one of his Twelve Labors.