Cujo is a 1983 American horror film based on Stephen King's 1981 novel of the same name and directed by Lewis Teague. It was written by Don Carlos Dunaway and Barbara Turner (using the pen name Lauren Currier), and starring Dee Wallace, Daniel Hugh Kelly and Danny Pintauro.
The film follows a mother and her son who are trapped inside their car, while protecting themselves from a rabid St. Bernard.
Despite receiving mixed reviews and being a modest success during its theatrical release, the film has gathered a cult following in the years since its release. It was released four months before Christine, which is another Stephen King story that gained a theatrical release the same year.
Cujo, a friendly and easygoing St. Bernard, chases a wild rabbit and inserts his head into a cave, where a rabid bat bites him in the nose. Meanwhile, the Trenton family — advertising executive Vic (Daniel Hugh Kelly), housewife Donna (Dee Wallace) and their sensitive young son Tad (Danny Pintauro) — take their car to the rural home of abusive mechanic Joe Camber (Ed Lauter) for some repairs, where they meet Cujo, the Camber family's pet, and get along well with him.
Donna notices Cujo's bitten nose, but thinks little of it. Later, Vic and Donna's marriage is tested when Vic learns that Donna is having an affair with her ex-boyfriend from high school, Steve Kemp (Christopher Stone), while Vic's advertising for a cereal commercial is failing. The early signs of Cujo's infection start to appear, including sensitivity to loud noises, and fraying temper producing soft growls, but no one notices these changes in his behavior. Charity (Kaiulani Lee) and Brett (Billy Jacoby), Joe's wife and son, leave the house for a week to visit Charity's sister Holly. On the morning of their departure, the furious stage of the infection begins to set in; though Cujo refrains from attacking Brett, he soon goes completely mad and kills the Cambers' alcoholic neighbor Gary Pervier (Mills Watson). Shortly afterwards, Joe goes to Gary's house and finds him dead, then tries to call the authorities just before Cujo appears and attacks him.
Vic goes out of town on a business trip, as Donna and Tad return to the Camber's house for more car repairs. Cujo attacks them, and they are forced to take shelter in their Ford Pinto. Donna tries to drive home, but the car's alternator dies and the two are trapped inside. The hot sun makes conditions nearly unbearable, and Donna realizes that she must do something before they both die from heatstroke or dehydration. However, attempts at escape are foiled by Cujo repeatedly attacking the car, breaking a window in the process, and even biting Donna. Vic returns home to rekindle his marriage, only to find Donna and Tad missing and his house vandalized by Kemp. He suspects the possessive Kemp of kidnapping, but the police realize his wife and son might be at the Camber's house.
The local sheriff, George Bannerman (Sandy Ward), arrives at the mechanics house and has a brief standoff; before he can draw his gun, Cujo kills him, knocking him off the catwalk in the barn and mauling him to death. Later, Donna attempts to get to the house to bring a dehydrated and overheated Tad water, but is stopped by Cujo; she fights him off with a baseball bat until it breaks, leaving only a jagged handle. Cujo jumps at her and is impaled in the stomach by the broken bat. Donna takes the sheriff's gun and contemplates shooting him, but decides saving Tad is more important. After Donna revives Tad inside the kitchen, Cujo, now recovered, breaks through the kitchen window and tries to attack Donna. However, Donna shoots Cujo dead, before Vic arrives and reunites with his family.