My Ending to Rosemary's Baby
In my mind, after the credits roll this is what i imagined happened:
Rosemary plays it off that she wants to be the baby's mother, and picks it up over her shoulder, patting it on the back, and walking around with it. Once all the cult members accept her new attitude, and are relaxed, she crashes head first out the window, plunging to her and the baby's death.