Origin

Hedorah came to earth as alien spore attached to a meteor whose path was close to Earth. The primitive creatures quickly mutated in contact with industrial waste and by gathering together the micro-organisms evolved through four stages of development into a gigantic form made of sludge that moves onto the land in search of more concentrated forms of pollution, spewing sulfuric acid mist and disintegrating every living thing unfortunate to be caught in its path.

The creature is able to incarnate eitehr as a standing creature or a monstrous frisbee-like flying form, invulnerable to conventional attack because of its changing soft nature, Hedorah was eventually victim of dehydratation that dried its whole mass.