Rat (1970)

A frustrated writer named Drew Larson. With an acclaimed short story to his credit who turns to academia because each time he’s got a good book idea, something terrible happens. He is determined to write an idea for a Western, and heads out to an old family cabin in the woods determined to get it done. Severe storms occur and he makes a Faustian bargain with a rat to alleviate his writer’s block. Larson believes it was done in a dream state of delirium, but finds when he returns home that he made a rat pact to trade success for the life of a loved one…