Hellhound is a mythical creature that is often described as a monstrous dog or wolf. Synonyms for this ferocious beast include Cerberus, the three-headed dog that guards the gates of the underworld in Greek mythology, and Garmr, the giant hound that guards the gates of Hel in Norse mythology. Other synonyms for hellhound include Black Shuck, a ghostly black dog from English folklore, Barghest, a monstrous dog from northern England and Scotland, and Cù Sìth, a faerie dog from Scottish and Irish mythology. Regardless of the name, these creatures are thought to be harbingers of death and destruction, bringing terror to those who cross their path.