Grindhouse: Wolfwoman (DVD)

On the night of the full moon, deep within a forest, a beautiful young woman starts a rhythmic, ritualistic dance into a circle of fire... As she reaches a frenzied climax, she collapses on the ground, writhing and groaning as her pure skin and lovely features assume the ugliness of a wild animal. She leaves a trail of bloody killings across the country-side as she runs for her life.