Shin Godzilla was mutated by feeding on nuclear waste dumped into Tokyo Bay in the 1950s, which gave it the unusual ability to mutate its own DNA and rapidly evolve itself to adapt to new situations. Shin Godzilla remained underwater until 2016, when it suddenly developed legs and came ashore in Tokyo, leaving behind a trail of destruction. Godzilla evolved once again into a third form before returning to the ocean. It later returned in a larger fourth form, which annihilated much of Tokyo 