Pachycephalosaurus (meaning "thick headed lizard"), was the last, largest, and most famous member of the thick-headed dinosaurs. It existed during the Late Cretaceous period in what is now North America.
A new set of clones was created by InGen for Masrani Global Corporation's Jurassic World. These new clones were close to the size of the originals. The new clones' skin was dark red with lime spots and a lime underbelly. They resided in the self-titled Pachy Arena where visitors could watch them have on of their famous head-butt duels. Everytime they butt heads, their inplants became temporarily disabled, which allowed the Pachycephlosaurs to escape the Pachy Arena without being tracked.