Godzilla Godzilla vs. Hedorah
aka Godzilla vs. the Smog Monster
from TMDB: An ever evolving alien life-form arrives on a comet from the Dark Gaseous Nebula and proceeds to consume pollution. Spewing mists of sulfuric acid and corrosive sludge, Godzilla may not be able to defeat the toxic menace.
1971 feature, Blu-ray format