Cerberus (Highway to Hell)

Cerberus is a large three headed, monstrous dog that feasts on human flesh and guards the gates to Hell City. His only job is to let people who are truly dead to pass through the city and to eat those who have entered Hell by some other means, however in the movie a man named Charlie Sykes entered Hell through opening a magical portal and was able to sneak past Cerberus by using his dog as a distraction. Charles was then able to get into Hell City and eventually save his girlfriend and escape from hell.