Dinosaurus is some type of temporal being that is able to come into the present through a unwitting teenager.
Dinosaurus was created by Robert Kirkman and Ryan Ottley. He first appeared in 2009's Invincible #68.
Major Story Arcs
Dinosaurus first showed up after the Invincible War when he tried to stop Invincible and his fellow heroes from helping to clean up the damage left after the war. He felt that the world would be a better place if it recovered without help and slowly instead of quickly. After a brief battle with Invincible, Dinosaurus reverted back into his teenage host and Invincible almost decided to kill the kid to keep the villain from returning, but he was stopped by Robot.
The teenage boy was incarcerated in Stronghold Penitentiary, but eventually after the Viltrumite War he unwillingly turned back into Dinosaurus and escaped.
Not long after his escape, Invincible confronted the rampaging Dinosaurus in Las Vegas. During their fight, Dinosaurus tells Invincible that he was actually just trying to scare everyone away from the city, after which he would level the city with a bomb, destroying what he considered a man-made blight on a naturally-created desert. Invincible quickly took away the bomb, but Dinosaurus then revealed that he had over fifty bombs planted throughout the city, making him uncertain whether he himself would survive the blast. The bombs then suddenly detonated all at once, wiping out Las Vegas and leaving only a giant sheet of glass where the city once stood.
Not having the resources to rebuild Las Vegas, Cecil Stedman and the Global Defense Agency (with government approval) end up turning the site of Las Vegas into a giant solar power plant, one that will power nearly half the country and employ thousands of people. Realizing that Dinosaurus was actually on to something with his plans for humanity, Invincible tracks down him and breaks him out of prison. He did this mainly by using the human's weakness; indifference. Dinosaurus was so bored by Invincible's origin he transformed and assisted the hero. Invincible then proposes to help Dinosaurus with his plans, so long as he doesn't recklessly endanger innocent people.
Invincible and Dinosaurus later come to the aid of Earth's various heroes after they were defeated by the newly-returned villain, Omnipotus, who was now even more powerful than he'd been before. Omnipotus at first seemed to have the upper hand over the duo, until Dinosaurus managed to sneak up on him and crush the villain's head between his jaws, presumably killing him. Following Invincible's exposure to the new Scourge virus, Alan, the Alien sought out Dinosaurus to help him find a cure to Invincible's condition. Infected, Mark was taken to Thragg's ship on the Moon to be treated. It was soon revealed by Thragg's scientists that Mark and Nolon were part of the original bloodline of the Viltrumite King. Knowing he could never have a traitor taking over his roll, Thragg decided to secretly kill Mark until Dinosaurus stepped in and fought Thragg, but was almost killed in the process. Dinosaurus used timed explosions to escape with Mark to his secret base on Earth.
Powers and Abilities
Dinosaurus has considerable strength and durability, showing to be capable of going one-on-one with Invincible. He's even managed to critically injure the cosmically-empowered villain, Omnipotus. His claws and teeth are also very tough, having been shown to easily tear through both concrete and steel. Despite his savage nature, Dinosaurus has also demonstrated considerable intellect in his plans to change the world, although he typically executes them in very reckless and destructive ways.
When Dinosaurus reverts back to his teenage host, the boy has little to no recollection of what happened, although he has been shown to be aware of the fact that he sometimes forcibly changes into Dinosaurus, and that he in no way consents to what Dinosaurus does.