Il était une fois le diable - Devil Story

A deformed Quasimodo type in a tattered military uniform stalks the French countryside, slaughtering any poor soul who gets in his way. A young couple's car breaks down dangerously close to the mutant and, after an inexplicable hallucinatory experience, the wife convinces her husband that it would be in there best interest to vacate the premises. By nightfall they find shelter from a raging storm in a suspicious gothic manor.