Old weird sci fi movie

Movie is a bit odd. It's about this young guy who wants to build the perfect girl out of spare parts. It's not "weird science" I think this young guy kills alot of the girls. In one scene he puts this leg into this girls room where they are having a slumber party and it zooms around in there room and then I think it kills them all or something. At the end of the movie he creates the girl and I think she ends up running away or something. I know it doesn't have a happy ending. Although the movie sounds dark it was pretty comical from what I remember. Anyone remember?