Toho's Godzilla looked more dinosaur-like before he was transformed by the atomic bomb test. Godzilla's origin story has changed several times over the years, but the most consistent aspect of the story is that an atomic bomb test created him as he is today. Godzilla has been reimagined since then, but in sticking with the original depiction, nuclear weapons always play some sort of role.
In the original 1954 movie, Godzlla was born when the United States military conducted an atom bomb test in the Pacific Ocean. The use of a nuclear weapon woke up a prehistoric reptile who had been sleeping at the bottom ocean. The atom bomb also bombarded his body with nuclear radiation, turning him into a towering monster capable of leveling buildings and bringing great destruction with his atomic breath. The Japanese government killed the beast with the Oxygen Destroyer, but Toho revealed the existence of a second Godzilla in the sequel, Godzilla Raids Again.
Godzilla has been reintroduced and rebooted several times since then. The movies have had different takes on how Godzilla was created, but only one classic Toho film has shown audiences what Godzilla was prior to his transformation. In the third installment in the Heisei series, Godzilla vs. King Ghidorah, time travel was used to revisit a moment from Godzilla's past. A scene on Lagos Island in 1944 revealed that Godzilla was once a dinosaur called a Godzillasaurus, who became a hero to a group of Japanese soldiers after saving them from the Americans.
The Godzillasaurus stood at about 40 feet tall, which is tiny in comparison to all versions of Toho's Godzilla, but despite being significantly smaller, he can easily be recognized as the monster's precursor. The creature, who has more physical qualities of a dinosaur than Godzilla does, has the small arms of a T-Rex, and the distinctive face of the 1990s Godzilla. Also, the Godzillasaurus is missing Godzilla's trademark back spikes. Instead, he has ridges all down his back and tail. Unsurprisingly, the Godzillasaurus is powerful, but far from unstoppable. He was able to devastate the American forces by stomping on and crushing them with his tail, but he couldn't hold up to the rocket launchers, gunfire, and missiles that were unleashed on him. He also possessed his own roar, rather than the iconic Godzilla roar.
The reason Godzillasaurus bears some similarities to the T-Rex is partly because he was supposed to be a T-Rex in the first place. Toho considered a whale design for Godzilla vs. King Ghidorah, before leaning toward a T-Rex. But in the end, it was decided that Godzilla should originate from a unique dinosaur species. What Toho ultimately came up with was a perfect fit, as it looks like the kind of creature one would imagine Godzilla could have evolved from. The Godzillasaurus was an interesting addition to the Godzilla mythos, as it answered one of the biggest questions concerning the King of the Monsters and added a new layer to his origin story.
