A creature often depicted as a guardian of gates in various mythologies is the Chimera, a monstrous being with a lion's head, a goat's body, and a serpent's tail, embodying the concept of protecting thresholds between worlds. However, more traditionally, figures like Cerberus, the three-headed dog from Greek mythology, serve as the guardian of the gates to the Underworld, preventing the dead from leaving. These guardians highlight themes of boundary, transition, and the cycle of life and death.