Pachyrhinosaurus was a large, plant-eating dinosaur that had a bony, spiked neck frill, four short legs, and a short tail. "Pachyrhinosaurus" was a short-frilled ceratopsian dinosaur that was 18 to 23 feet (5.5 to 7 m) long. "Pachyrhinosaurus" had many small horns on the middle of its frill. 