Bog is a 1978 horror film set in America. Dynamite fishing in a rural swamp revives a prehistoric gill monster that lives on the blood of human females. When a local is fishing with dynamite in Bog Lake, something larger pops to the surface: a green bug-eyed monster awakened from a long sleep, which promptly begins killing fishermen who stumble across its lair. When biologist Ginny Glenn (Gloria DeHaven) discovers the creature's evolutionary nature, the local sheriff decides to use various methods to destroy the beast.