Agathaumas ("great wonder") is a dubious genus of a large ceratopsid dinosaur that lived in Wyoming during the Late Cretaceous (65 million years ago). The name comes from Greek, "αγαν" - 'much' and "θαυμα" - 'wonder'. It was seen as the largest land animal known at the time of its discovery and might be a synonym of "Triceratops". It was related to "Ceratops".