From from the 1971 film Godzilla vs. Hedorah, Hedorah came from the Dark Gas Nebula and fed on pollution, hence its alternate name of the Smog Monster. Falling to Earth as a cloud of spores, Hedorah hatched into millions of microscopic tadpole-like organisms which began to feed upon mankind’s pollution. As they increased in number and power, they began to merge into a giant monster of living sludge capable of reducing the entire planet to an uninhabitable wasteland.
Interesting about this kaiju is that is appears in three forms: a land form, a flying form, and a water form. All have the detailed, blood red eyes; the dark, unctuous body; and the glowing head for a truly disturbing look.