The film takes place along a stretch of coastline somewhere in Florida, where a local tourist spot has become plagued by a mysterious marine creature.

Unbeknownst to them, the monster is the product of a secret military experiment; it is a genetic hybrid mutated from a common octopus and the prehistoric Dunkleosteus.

They eventually find it hiding in the Everglades, corner it in shallow waters, and kill it with repeated blasts from flamethrowers.

[3] Star Michael Sopkiw attributes the film's flaws and negative reviews to the production's limited budget, saying that Lamberto Bava was a great director.

On August 15, 1998, Monster Shark, under its alternative title of Devil Fish, was featured on an episode of the movie-mocking television series Mystery Science Theater 3000, on which it was spoofed for its poor acting and erratic editing.