Cujo

Cujo is a two-hundred-pound Saint Bernard and the best friend that ten-year-old Brett Camber ever had. One day, Cujo pursues a rabbit into a bolt-hole and gets bitten by a rabid bat. Suddenly, the once-friendly St. Bernard turns into a killer.

Donna Trenton's husband is in New York trying to contain a disastrous ad campaign. Feeling abandoned by her workaholic husband, who is frequently out of town, Donna Trenton embarks on an affair with a local handyman. Left to fend for herself, she takes her ailing Pinto to Joe Cambers' garage for repairs--only to be trapped with her son Tad in the sweltering car by the monstrous dog.