A young boy named Billy gets yelled at and slapped by his father, Stan, for reading a horror comic titled Creepshow. Stan reminds his wife that he had to be hard on Billy because he does not want their son to be reading such "crap". As Billy sits upstairs cursing his father with hopes of him rotting in Hell, he hears a sound at the window, which turns out to be a ghostly apparition in the form of The Creep from the comic book, beckoning him to come closer.
Dr. Robert "Rack" Hansen (Shatner), a veterinarian in rural Verde Valley, Arizona, receives an urgent call from a local farmer, Walter Colby (Woody Strode). Colby is upset because his prize calf has become sick for no apparent reason, and the animal is brought in to Hansen's laboratory. Hansen examines the calf, which dies shortly afterward. Hansen tells Colby he cannot explain what made the animal so ill so quickly, but takes samples of the calf's blood to a university lab in Flagstaff.
Two teenagers come upon an apparently abandoned military installation. They take advantage of what appears to be a swimming pool to skinny dip. The teenagers are attacked by an unseen force and disappear under the water. A light activates in the main building and a silhouetted figure investigates the screams, but is too late to help.
Martin, CEO of Tri-Oceanic Corp, hires geologist Steven Beck to command an undersea mining operation for six months. While working outside their deep sea station in a pressure suit, one of the crewmembers, Sixpack, discovers a Soviet shipwreck, Leviathan.
In Burundi, a British forensic anthropologist is examining the corpses in a mass grave, claiming they were all killed in an identical manner. When the woman digs her shovel into what she believes is another grave, an unseen creature attacks, and violently drags her into the river. The UN soldiers accompanying her fire into the water, but only her partially devoured corpse floats to the surface, before being devoured.
The movie revolves around the exploits of Captain Nolan (Harris), an Irish Canadian who catches marine animals to pay off the mortgage of his boat, and return to Ireland. Nolan's crew is looking for a great white shark for a local aquarium, but a scientist named Ken (Carradine) is being targeted by the shark. An orca comes and kills the shark, saving Ken. This switches Nolan's target to the orca. While Nolan is on the journey with his crew, he tries to capture what he believes to be a bull orca, but mistakenly harpoons a pregnant female. Nolan and his crew get the orca on board, where she subsequently miscarries. The crew hoses the dead fetus overboard as the male looks on screaming.
Willard is a meek social misfit who later develops a strange affinity for rats. He lives in a large Victorian home, with only his cranky and decrepit mother for company. On his 27th birthday, he is humiliated to come home to a birthday party thrown by his mother, where all of the attendees are her own aging friends. After having left the party in embarrassment, he notices a rat in his backyard and tosses it pieces of his birthday cake. Later, his mother gets upset with him for leaving the party and she scolds him later while also discussing how badly the house is falling apart. The next morning he goes out and feeds another rat (this one has babies with it) while imitating their squeaks. His mother starts telling him that he needs to kill the rats that have been running around their yard, which Willard refuses to do.
Judy Sanders (Robin Frates), an employee of a genetic research facility named EMAX, contacts TV personality Lori Tanner (Ally Sheedy), planning to meet after work so she can show Lori the atrocities and animal cruelty that go on in EMAX's laboratories. Dr. Jarret (Lance Henriksen), a scientist performing vivisection and genetic altering, discovers the plan and sets one of his experiments on Judy, killing her. Lori arrives at EMAX, but when Judy does not appear, she breaks into the laboratory and films the various animals that are being experimented on. She discovers a Tibetan Mastiff named Max who does not appear to have been experimented on and lets the dog out of his cage. Dr. Jarret discovers that there is an intruder in the laboratory and chases Lori out of the building, with Max following Lori into her car as she drives away. Jarret immediately goes to the police and complains that his dog has been stolen. Later that day, when Lori goes shopping, a mugger (Thomas Rosales, Jr.) steals her purse. Max chases the thief, brutally kills him, and brings Lori's purse back to her.
When an abandoned textile mill is reopened, several employees meet mysterious deaths. The link between the killings being that they all occurred between the hours of 11 p.m. and 7 a.m.—the graveyard shift. The sadistic mill foreman (Stephen Macht) has chosen newly hired drifter John Hall (David Andrews) to help a group clean up the mill's rat-infested basement. The workers find a subterranean maze of tunnels leading to the cemetery—and a bear-sized, hairless, bat-like creature that hunts at night. In the end, Hall is able to kill the giant bat when it gets caught in the grinding wheels of a cotton picker and crushed to death.
Melanie Daniels (Tippi Hedren), a young socialite, meets lawyer Mitch Brenner (Rod Taylor) in a San Francisco bird shop. He wants to purchase a pair of lovebirds for his sister's eleventh birthday, but the shop has none. He recognizes her from a previous encounter, but she does not remember him, so he plays a prank by pretending to mistake her for a salesperson. She is infuriated when she realizes this, even though she also likes to play practical jokes. Intrigued, she finds his address in Bodega Bay, purchases a pair of lovebirds, and takes the long drive to deliver them. She secretly deposits the birdcage inside his mother's house, with a note. He spots her on the water through a pair of binoculars during her retreat, and manages to talk to her after she is attacked and injured by a seagull. He invites her to dinner, and she hesitantly agrees.
Amidst a storm, a boat is being piloted across the South China Sea by John Finnegan (Treat Williams). With him are his crewmen Joey "Tooch" Pantucci (Kevin J. O'Connor) and Joey's girlfriend Leila (Una Damon). Finnegan has been hired to transport a group of mercenaries, led by a man named Hanover (Wes Studi), to an undisclosed location in the middle of the ocean.
After people start to die in the small Texas town of Gallup, the prime suspects are bats. The CDC calls in Dr. Sheila Casper (Dina Meyer) and her assistant, Jimmy Sands (Leon Robinson), who are zoologists who specialize in the study of bats, to investigate the situation. Dr. Alexander McCabe (Bob Gunton) is secretive about the situation, but admits that the bats were genetically modified by him to become more intelligent and also omnivorous so they wouldn't be in danger of extinction any longer. Sheila is disgusted by this but it seems that McCabe had the best intentions.
Seven Tulane University undergraduates – Sara, Nick, Beth, Malik, Maya, Blake and Gordon – drive to Sara's family vacation home on a private lake. There, Sara encounters her old boyfriend, Dennis, and his friend Red.
Willard Stiles (Crispin Glover) is a social misfit taking care of his ill and fragile but verbally abusive mother Henrietta (Jackie Burroughs) in a musty old mansion that is also home to a colony of rats. Willard finds himself constantly humiliated in front of his co-workers by his cruel boss, Frank Martin (R. Lee Ermey), a vicious man who assumed control of the company from Willard's father upon his death, and whose professional interest in Willard extends to a personal financial one. A co-worker, Cathryn (Laura Elena Harring), has sympathy for the quirky Willard. Cathryn becomes Willard's friend and love interest.
A year after the attack on Lake Victoria by prehistoric piranhas, an eradication campaign has left the lake uninhabitable, and the town itself has been largely abandoned as a result of the drying-up of the Lake. Meanwhile at Cross Lake, two farmers (Gary Busey and Clu Gulager) search the waters to recover the body of a dead cow. Piranha eggs that have been laid inside the cow hatch, and the farmers are killed by the swarm, but before they both die, one farmer pops out of the water, takes a piranha, bites it, and then spits it up before sinking back into the water.