Skin sliding off like slipping out of shirt, hair and teeth falling out, eyes & ears bleeding, right before all the connective tissue in the body gives way.
Or using "The Audition" for inspiration, have some tempting gymnist charm/seduce/suggest a PC to go home with her; she cuts his tongue out, dismembers him, then keeps him alive, blind, deaf & dumb, in a bag of holding. She then seduces other men into buying her dinner, then goes home alone to vomit in a bowl to keep her girlish figure as well as to supply the captured PC with nourishment. Add in a PC getting strangled or decapitated with razor wire. Take it a step futher and have her give them something instead... a 'fiendish, gargantuan STD'.
Man, I'm gonna get a warning or something, but the movie is the scariest I have seen.