Cujo (1983)

Directed by Alligator helmer Lewis Teague, this adaptation of the terrifying Stephen King novel of the same name is the story of a rabid St. Bernard who terrorizes a small suburb, and especially mom Donna (Dee Wallace) and son Tad (Danny Pintauro), who spend much of the film trapped in their Ford Pinto, stalked by Cujo.
It works not just because of the when animals attack stuff, but also as a metaphor for the constant threats to domestic bliss. Early in the film, its revealed that Donna has been having an affair, threatening her marriage to Tad’s dad, Vic (Daniel Hugh-Kelly).