To Tommy's surprise, the zombies and the dinosaurs in his play box tended to steer clear of one another. He actually introduced the dinosaurs to clean up the zombie problem, which spawned from a plastic hippo implementing a necromancy scheme to bring back the melted crayon he claimed as his friend. But, the dinosaurs, for the most part, had little interest in the zombies, unless they were scavengers. And Tommy didn't keep many on hand any more since the incident with the meatloaf. The zombies found the dinosaurs to be too much work. Then t-rex ate the plastic hippo.