Cujo was a massive, male St. Bernard owned by the Camber Family. Cujo was once a friendly and playful companion, but when he got rabies from a bat bite, he went insane and was turned into a vicious killer that attacked anybody who came near him.
Cujo
During the events of the novel, Cujo was bitten by a bat and got rabies from it. For the next few days, he became very bloodthirsty and dangerous, eventually killing Gary Pervier and Joe Camber. When Donna Trenton and her son, Tad, go to the Camber's farm for an auto repair, they are attacked by Cujo and spend three days in their car hiding from him. By this time, Cujo is now completely covered in sweat, blood, grime, froth and mucus, and the smallest things could set him off. When the phone rings, Cujo flies into a rage and viciously attacks the car, breaking a window in the process. Cujo bites Donna in the leg when she tries to escape and get help, and she barely survives the merciless and destructive attack. Luckily, the sheriff arrives, only to be savagely mutilated by Cujo after a brief struggle.
Meanwhile, Tad is dying of severe dehydration and Donna decides that she has to do something or else her son will die. She makes a daring escape from the car and Cujo attacks. Luckily, Donna is able to grab a discarded baseball bat from a junk pile and fend the dog off. She beats the dog with the blunt instrument, but the breaks when it strikes Cujo's face. Cujo

A bloodied and crazed Cujo in the film.
In the book, Cujo's death is much more graphic. The end showdown is the same, but when Donna breaks the bat, she impales him in the eye with the sharp broken end, killing him instantly.
Other Appearances
Along with the posessed automobile Christine he makes a cameo appearence in "Cat's Eye" where he chases the titular cat General. He kills with multiple bite and scratch wounds.
Appearances
-
Stephen King's Cujo (1983) Cujo Attacks!
Cujo attacks Donna and Tad
- Cujo (film)
- Cat's Eye (cameo)
- The Tommyknockers (mentioned)
- Pet Semetary (mentioned)
- Needful Things (mentioned)
- The Body (mentioned)
- Creepshow 2019 (mentioned)
Audiobook
The audiobook verson of Cujo is read by Lorna Raver.