Devil Fish (1984)
An electrician and marine biologist team up to stop a mutant shark from its attacks.
In Miami, Florida, a Coast Guard helicopter is flying over the ocean when they come across a capsized boat. Two divers go in and they recover the body of a man. Dr. Stella Dickens is working with her dolphins including Donald when a tour guide brings a group of aquarium visitors to see her work. She shows them tricks she can do with Donald and tells them her associate, Dr. Bob Hogan, is conducting an experiment out at sea. Dr. Hogan is drinking a beer on his research vessel when the sonar alarm goes off and he starts recording the sound. At the same time, the dolphins start to act skittish. Sheriff Gordon and Cortez go to the morgue and ask Doctor about his opinion on what killed the victim picked up by the Coast Guard. He tells Sheriff Gordon, he thought at first the victim was killed by a shark, but the bite marks are too large. Dr. Dickens tells Dr. Hogan about the dolphins acting strangely and he plays the recording he made, but the sound wasn't recorded. They then realize the dolphins acted strangely at the same time Dr. Hogan noticed the noise.
Peter checks on how much work Sandra Hayes has done while he was gone and quickly fixes a machine she said she couldn't fix. Dr. Dickens stops at the repair shop and tells Peter she needs his help and gives him a list of equipment she needs built. Sonja West sneaks into the lab at West Ocean International and starts flirting with Dr. Davis Barker. They kiss and are seen by Florinda. Florinda has a conversation with Dr. Barker and tells him she is going to tell the press everything she knows. Sheriff Gordon shows Dr. Hogan photos of the attack victim. As Florinda is getting ready to leave, the doorbell rings and when she answers the door, Miller forces his way in. He attacks Florinda, puts her in the tub and then drops a plugged in hair dresser into it, killing her. Peter and Sandra are having sex when Peter hears someone break into the shop. He catches two men breaking the equipment he made for Dr. Dickens and as he is fighting them, is knocked unconscious by Miller. Fisherman and Fisherman 2 are out spear fishing on their boat when Fisherman sees a shark and panics. The shark swims away, but then the Monster Shark attacks them. Sheriff Gordon and Cortez investigate the death of Florinda and Sheriff Gordon thinks it is odd that Florinda called for a taxi and then took a bath. Professor Donald West, Dr. Barker and Sonja are interviewed by Sheriff Gordon and Professor West tells him Florinda was researching ribonucleic acid. A boy is running on the beach with his dog when he finds Fisherman 2 dying on the beach. Fisherman 2 is brought to the hospital and the Doctor tells Sheriff Gordon that the men were attacked by the same thing that attacked the first victim and shows him a cast made of a large tooth.
Peter and Sandra deliver the equipment to Dr. Dickens and Dr. Hogan. Peter, Dr. Dickens and Dr. Hogan go out to sea and briefly spot the Monster Shark on sonar. Dr. Barker pays Miller for murdering Florinda. Dr. Hogan tells the others that the Monster Shark has been picked up on sonar again and they record the sound it makes. Fisherman 2 dies of a heart attack and Sheriff Gordon tells the Doctor, he died of fear. Dr. Dickens and Peter bring the record to Dr. Barker and Sonja and ask for their cooperation and Professor West agrees. Dr. Hogan calls the Paleontological Institute and speaks with Dr. Janet Bates and asks her to bring her notes on proto-sharks. Carl and Molly are on their boat when they are attacked by the Monster Shark. Carl is killed and then Molly is. Dr. Bates gives a lecture on prehistoric sharks to Peter, Dr. Hogan, Dr. Dickens, Cortez and Sheriff Gordon and she tells them she thinks the Monster Shark is a living fossil. Sheriff Gordon wants to kill the Monster Shark, but Dr. Hogan and Dr. Bates want to capture it. Miller walks up to Sandra who wants out of their arrangement, but Miller tells her that she will do what they want. After Miller leaves, Sandra tries to call Sheriff Gordon, but Miller catches her and hangs up the phone. Peter, Dr. Dickens, Dr. Hogan and Dr. Bates go out onto the ship again. Professor West tries to login to the Sea Killer file, but his access is denied.
Peter and Dr. Dickens find their equipment destroyed and have sex on the beach. Dr. Hogan and Dr. Bates catch an image of the Monster Shark and see that it has tentacles. The Monster Shark attacks the ship and Dr. Hogan is killed. Peter and Dr. Dickens return to the ship and find Dr. Bates still alive. Sheriff Gordon, Cortez and Peter give Professor West and Dr. Barker the data on the Monster Shark and its DNA shows the Monster Shark is only eight months old. Peter comes up with an idea to mimic a mating call to attract the Monster Shark. Peter, Dr. Dickens and Dr. Bates go back out to sea and try Peter's idea. Sheriff Gordon works with the Coast Guard to try and blow up the Monster Shark with explosives. Dr. Barker calls Miller and tells him to stop Peter and Dr. Dickens. Cortez tells Sheriff Gordon that Sandra was found murdered. Miller takes a boat out to Dr. Dickens' ship and attacks Dr. Bates and shoots her dead. Two men attack Peter and Dr. Dickens while they are diving, but Peter kills one of them and the Monster Shark kills the other. Miller ties up Dr. Dickens, who had escaped, and Peter knocks Miller into the water. The Monster Shark grabs and kills Miller. Peter and Dr. Dickens find Dr. Bates dead. Professor West calls Sheriff Gordon and tells him the Monster Shark can produce asexually from any part of its body and Sheriff Gordon tells dispatch to have the Coast Guard remove the explosives. Professor West manages to get into the Sea Killer file and finds out Dr. Barker created the Monster Shark. Dr. Barker and Sonja tell Professor West why they created the Monster Shark and as Dr. Barker is about to shoot Professor West, he is shot by Sheriff Gordon and dies. Cortez arrests Sonja and Professor West tells Sheriff Gordon, fire can kill the Monster Shark. Peter creates a device which plays the mating sound and Sheriff Gordon and the Coast Guard wait to burn the Monster Shark with gasoline. The Monster Shark attacks and kills a group of Coast Guardsmen, but is then set on fire and killed. Later, Dr. Dickens drives to Peter's shop and he tells her, he is going on vacation to the mountains.