Devil Dinosaur was a dinosaur character who resembled a small red Tyrannosaurus rex. Devil Dinosaur's constant companion was the primitive, ape-like Moon-Boy. Their adventures took place in 'Dinosaur World,' a land in a parallel universe where dinosaurs co-exist with tribes of primitive humanoid beings.
The young Devil Dinosaur was nearly burned to death by a tribe of Killer-Folk, hostile beings native to his planet, but was rescued by Moon-Boy, a young member of a rival tribe, the Small-Folk. Exposure to the Killer-Folk's fire activated a mutation in the dinosaur which gave him powers greater than others of his species and turned his skin from olive green to flame red. Devil Dinosaur is fiercely loyal to his constant companion Moon-Boy and seems more intelligent than the average dinosaur (as they are portrayed in the comic).
Devil Dinosaur and Moon-Boy were created by artist Jack Kirby who scripted and penciled all nine issues of the first series. Devil Dinosaur was created during Kirby's third stint at Marvel (1975–1978) with the original series being produced with hopes of being picked up as an animated series. Seventeen years earlier Kirby had penciled Amazing Adventures #3 (August 1961) in which a time-traveling couple encounter a red Tyrannosaurus rex similar in appearance to Devil Dinosaur.