Godzilla

Godzilla was once a dinosaur known as a Godzillasaurus, who somehow survived the extinction of the dinosaurs and dwelt on Lagos Island, where he once saved a Japanese platoon in WWII in 1944. Ten years later after the death of the creature, H-Bomb testing started to increase, and when the H-Bomb hit Lagos Island, the dinosaur mutated into the creature known as Godzilla. It became far larger, stronger, and more powerful, and gained a radioactive atomic ray; the monster was unstoppable--or so it was thought. When a device called the oxygen destroyer killed the original Godzilla, a new Godzilla was born, who was even bigger and stronger, with a more powerful atomic ray, minor regeneration abilities, and thicker skin. (1)