French nuclear tests in the South Pacific mutated a kimodo dragon into a giant monster. After attacking and sinking a Japanese fishing vessel, it was mistakenly identified as Godzilla by the sole survivor. It went on to find its way to New York City where it went on a rampage. It was eventually destroyed by the American military forces, but not before laying some 100 eggs in Madison Square Garden. After the eggs hatched, all the newborns were destroyed except one, which had somehow managed to escape. The escaped newborn presumably found a new home, somewhere in the South Pacific, where presumably grew to adulthood unmolested and in peace. It was not seen again until its attack on Sydney, Austrailia. It was later forced by the Xilian Spacemen to fight the real Godzilla and was ultimately roasted to death by a blast of Godzilla's devastating atomic fire breath. Zilla's genetic structure contained a gene called M-Base which gives the invaders control over mutant monsters.