The Twilight Zone Season 3 Episode 11

A woman terrorized by her abusive husband finds some small consolation in a statue of a dog given to her by her sympathetic sister. The woman soon discovers that she can summon the dog to life as a huge ferocious beast that will respond when her husband abuses her. He manages to break the statue but the dog is not sent away. Begging for his life, she decides to simply leave, accepting the dog into herself. He tries to stop her but the dog is still there when she needs it.