Monster of the Day: Possessed Old Lady

Source:  Evil Dead II
Location:  In the woods, in the cabin in the woods, in the fruit cellar in the cabin in the woods
Threat Assessment:  5.  You wouldn't think an old lady would have it in her, but powered by demon juju she kicks butt.  Capable of great strength and limited shape changing ability, she is also extremely hard to kill.
Limitation:  There's still a human in there and sometimes that little bit can be reached, also removal of all limbs will stop the threat (but then that works for nearly everything.)