What is Oxygen Destroyer?
1.
A device created by Dr. Serizawa in the original 1954 'Godzilla' film.
The device is a weapon of mass destruction, able to completely wipe out oxygen in a given area.
The professor has a dilemma. He must destroy the device before it falls into the wrong hands. But, should he use it against Godzilla?
In the end, he sacrifices himself, and uses the Oxygen Destroyer to kill both him and Godzilla, so the Oxygen Destroyer will never be created again.
HOWEVER, precambrian life forms in the ocean soil mutated over the course of 41 years. These creatures destroy the oxygen in living organisms. The precambrian microbes mutate into 'Destroyah'. The Destroyah starts out in many juvenile crab-like forms, then joins together as an aggregating giant crab form, then a flying form, and a final form with massive wings.
Of course, he is killed by Godzilla and the JSDF
Oxygen Destroyer: the only way that man has been able to stop Godzilla.
(Aside from Mechagodzilla 1993, of course, which was thwarted by Rodan. Had Rodan not interveinved, Godzilla would not have survived without his other brain)
See