The Chasmosaurus is an animal encountered in Primal Rift.
The first Chasmosaurus can be found on the 3rd floor eating pizza. If the player brings a slice of pizza near him the Chasmosaurus will follow the player, crushing office furniture that gets in the way.
The second Chasmosaurus can be found on the 4th floor drinking water on the floor. Craig will comment that the Chasmosaurus should go downstairs to get pizza.