There were two females. Marnada was the older one and the younger one was I think called priscilla. Anyway they would transform into a cat but only one at a time. So priscilla found a man with I think two kids and was trying to get married to him. The next I remember is the females couldn't take pictures/ or look at a mirror b-cuz they will appear as a cat. One part of the movie the guy was trying to have sex with her and her cat tail started rising from the bed sheets. At the ending of the story someone found out about the two and stuck both of them into the cat and the house got sucked into the ground. I think it's called wicked stepmother but not so sure please help/

I think you are right about the title. It has Bette Davis in it.