Saw this on Bravo when Bravo still showed art movies. It had subtitles. R

Sister is electrocuted while in a bath (milk, I think). Her brother, possibly her twin, puts her body in a bass fiddle case and drives around the countryside.

I think he might have started physically transforming into his sister, but the movie is starting to fade. The bass fiddle case on top of the car is still vivid, though.

Thank you!