A Horrorsaurus, despite being a dinosaur, has the characteristics of an octopus and various other reptiles. It has tentacles, and a Predator-like maul. It has horns on the sides of its head, and carnivorous teeth. It is shown to have no visible limbs except for its tentacles. It has four eyes on the side of its head.
In the Futures Trading timeline, it is shown that the dinosaurs who have taken over the earth have developed an artificial dinosaur called the Horrorsaurus. It is revealed to Dr. Mcninja that the first Horrorsaurus had been killed by his parents, Mitzi and Dan Mcninja, by letting themselves be devoured by the Horrorsaurus and blowing up the bombs they had strapped on their bodies, sacrificing themselves in the process. The second Horrorsaurus was revealed in the battle between the dinosaur government and the human resistance, and was used to counter the giant lumberjacks that were produced by Dr. Mcninja's former patients diagnosed with Paul Bunyan's Disease. It managed to kill a few lumberjacks but was killed by the NASAghast after it killed Chuck Goodrich.
- Flight - It is capable of flying, although it has no wings or any flight supporting gear.