Cujo?

Devon the dog slept over at Bill's last night. Bill said that sometime in the wee hours of the morning, he was awakened by the sound of Devon growling menacingly. Bill got up and saw Devon sleeping in his usual corner, still growling. Then the doggie, still fast asleep, started barking. Bill said these were angry-sounding growls and barks! Yikes! Quickly, and from a distance, Bill told Devon to wake up, and he did. And all was calm again.

Whoda thunk it? Doggies get bad dreams?! You learn something new everyday...