Back in the Late Cretaceous, the USA was divided. Not politically, but by a vast continental sea called the Western Interior Seaway, splitting the continent into two separate landmasses. The western one of these, known as Laramidia, played host to some of the popular dinosaurs like Parasaurolophus, or ‘Elvis’ in Pete Postlethwaite dialect, and the ceratopsian Chasmosaurus. One of the cool things about Laramidia though, is that you had a whopping great amount of these megaherbivorous dinosaurs, or omnomnomosaurs, living together in the same time and place. How could one area contain such a vast number and range of dinosaurs?
Some dinosaurs were utterly bizarre. You may have heard of them before, but one particular group called therizinosaurs belonged to the meat-eating theropod dinosaurs (those that led to birds), were really awesome. However, they actually at some point made a conscious evolutionary decision to stop being badasses, and become Cretaceous-cauliflower* munching pansies.