Clatter was made when an experimental mutagen was dumped into the ocean and contaminated a single kaiju egg. When it hatched, it was heavily armored with a massive body, 4 strong limbs, and the strongest set of jaws in the kaiju world! It was discovered by scientists when it came up to feed on chum being used to lure sharks. It was tested and put into a swamp, where its strong, amphibious body was excellent at finding and eating carrion. It can speak, write, and do basic math. It protects its swamp with its life.