Hedorah, also known as the Smog Monster, is a kaiju from the Godzilla film series. It first appeared in the 1971 film 'Godzilla vs. Hedorah', directed by Yoshimitsu Banno. Hedorah is a unique monster, composed of toxic sludge and pollution, highlighting environmental themes of the era. It feeds on pollution, growing stronger as it absorbs more toxins, posing a significant threat to humanity and the environment. Its role in the series is as one of Godzilla's formidable adversaries, challenging the King of the Monsters with its ability to transform and adapt to different forms.