Cujo

Cujo is a huge Saint Bernard dog, the best friend Brett Camber has ever had. Then one day Cujo chases a rabbit into a bolt- hole. Except it isn't a rabbit warren any more. It is a cave inhabited by rabid bats.

And Cujo falls sick. Very sick. And the gentle giant who once protected the family becomes a vortex of horror inexorably drawing in all the people around him ... --back cover