Hell, Canto 6

Cerberus is a monstrous three-headed dog who stood guard over Hades, the Hell of classical mythology. Here in the Divine Comedy he stands guard over the third circle of Hell. He is always hungry, and will only allow Dante and Virgil to pass after they have placated him by throwing earth into his three mouths. It is the gluttons who are punished in this circle. Their fate is to lie wallowing in the mud like pigs, pelted by an endless storm of hail and snow, in the very opposite of luxury.

Compare this monster with those in Dante Running from the Three Beasts or Ghost of a Flea.