Ankylosaurus

The Ankylosaurus (known as the Ankylosaur prior to ) is a three-part fossil in the introduced in  that appears in all subsequent games to date.

Real-world information
Ankylosaurus was a large dinosaur that existed during the late Cretaceous period. It was a herbivore and the largest known ankylosaurine (characterized by bony armor and a tail club), reaching 6-8 meters (20-26 ft.) in length and weighing around 5 tons.