Discovered in Hell Creek, Montana, in 1983 and resembling a demon, this dinosaur was named Stygimoloch, which means "Styx Demon." The River Styx separated the Earth from Hades in Greek Mythology.
To date, two skulls have been discovered, both showing an abundance of long horns and studs all over the animals head.
Without any direct fossil evidence about its body, Stygimoloch is generally reconstructed based on close relatives such as Stegoceras.
Stygimoloch was a member of the Pachycephalosauria, or bonehead group of dinosaurs. This name refers to the very thick skulls that may have been used by these animals in head bunting competitions or to ram predators.