Godzilla vs the Smog Monster

 

A scientist who lives in Japan discovers a strange life new life form made out of mineral matter when the local fisherman brings him what appears to be a giant tadpole. He goes diving in order to find something- anything. His son sees the thing slicing through the water directly toward him. He tries to stab it with a knife but ended up getting his hand a nasty acid burn. The father who is still underwater sees the thing's eyes as it came closer...and closer... 
The father got half his face burnt off by the acid corrosion. It is determined that the new life-form is actually a "Hedorah", a smog monster, created by and gaining nourishment from the industrial pollution and all the yuk and gunk in the rivers, oceans, lakes and streams. Hedorah changes form several times in the film. It comes to Japan and sucks all the black smoke out of the smokestacks. Godzilla comes to pound on the Hedorah. 
Hedorah comes to Japan several more times, when he gains the ability to fly. Unfortunately, he produces sulfuric acid, which when it comes into contact with humans, kills them instantly, leaving nothing but skeletons. Such a pretty sight. ;) Godzilla finally cleans up the mess when he destroys the smog monster at the end.