Without a doubt, Godzilla is the most famous giant monster dinosaur around, but among the many supporting monsters that appeared alongside Big G over his long career was another aberrant dinosaur by the name of Gorosaurus.
Compared to other Toho Studio monsters, Gorosaurus wasn't all that special. A generalized theropod dinosaur reminiscent of some of the illustrations of Megalosaurus I saw during my childhood, Gorosaurus had no special powers or abilities other than being really, really big (about 100 feet tall). I guess that's why the fictional dinosaur was first used to show how powerful another monster was. During its cinematic debut in 1967's King Kong Escapes, Gorosaurus is hardly a match for the giant ape and suffered the same fate as the Tyrannosaurus in the original King Kong film. After it landed a few jump kicks, Gorosaurus had its jaws split open by the movie's primate star.
Gorosaurus did a little better in its second film appearance in 1968's all-out monster-brawl, Destroy All Monsters. Although initially transported from Monsterland to Paris by aliens with a plot to take over the world—really, if you're going to go to all the trouble of figuring out how to control the minds of monsters, you might as well get your money's worth out of it—Gorosaurus ends up breaking free of its mind control and joins its fellow monsters (Godzilla et al.) in duking it out with Toho's number one villain, the three-headed space dragon King Gidorah. Not too shabby for a monster originally conceived as a poor-man's Tyrannosaurus, and I have to admit that the ungainly creature is one of my favorite, lesser-known movie dinosaurs.