Baxter

Her daughter Florence gives Mrs. Deville bull-terrier Baxter as a surprise present. Although she's afraid of him, she doesn't want to give him away because she feels lonely. But Baxter has his own ideas - he longs to be dominated, to be challenged - and so he isn't content with his boring life with the old lady. To get rid of her, he causes an accident. It works, and he's given to the neighbors, a young couple. He's happy... for a while. When they get a baby, he again takes action. (imdb)