Stygimoloch
- Pronunciation: STIG-ih-MOE-lock
- Translation: Demon from the River Styx
- Order: Ornithischia
- Suborder: Marginocephalia
- Infraorder: Pachycephalosauria
- Family: Pachycephalosauridae
- Height: 4 feet (1.2 meters)
- Length: 6.6 feet (2 meters)
- Period: Late Cretaceous
- Description: Herbivore, Bipedaly
- Notes: Stygimoloch received its name from the unusual appearanceof its skull, which is adorned with three or four massive spikes, the largest of which was about 4 inches (100 mm) long. Like otherpachycephalosaurs, Stygimoloch may have used its horns in butting heads with rivals, like present-day Bighorn sheep.