Hedorah (ヘドラ, Hedora), also known as the Smog Monster, is a shapeshifting toxic pollution monster that first battled Godzilla in the movie Godzilla vs. Hedorah in 1971. Hedorah was named for hedoro, the Japanese word for sludge, vomit, slime or chemical waste.
Hedorah has a sludgy blob-like body and two extremely large red eyes. Hedorah has multiple forms, including a tadpole-like aquatic form, a reptilian terrestrial form, a saucer-like flying form, and a bipedal final form.
Hedorah is a colony of alien creatures from a distant galaxy that traveled to Earth in a meteor. The creatures fed on the Earth's pollution and grew, eventually combining with each other into one giant composite monster.