Hedorah is a monster from outer space who fed on pollution. In its first form, it resembled a tadpole. In its second form, it resembled a quadrupedal reptile. Its third form was like a flying saucer, and its final form took on a humanoid shape.
Hedorah's transformations are thought to be the inspiration for Destoroyah, who also went through transformations, of which he has four.
Hedorah is very curious and doesn't like long battles, so he tries to finish it as fast as possible, which is to say he enjoys finishing it quickly.
Hedorah's species can reproduce asexually, can combine with and separate from other species, and does not need oxygen to survive. This may confirm that all Hedorahs are genderless.