Funeral Home is one of a series of great slasher films in the early 80's that came from our brethren up north in Canada. It's also the film that introduces us to our next underrated villain in Grandma Maude Chalmers.
The story is Heather comes to her Grandma's place to help her open a bed and breakfast. Now this place used to be a funeral home (hence the title), but honestly, outside of a few creepy locations, it's really not that important. Rumor has it that Maude's missing husband ran off with another woman after Maude had a nervous breakdown...but if that's so, why does Heather hear her talking to a cranky old man down in the cellar?
Before too long people start showing up at the bed and breakfast, and then start disappearing. Maude isn't too keen on some of the guests, including Mickey from Meatballs with his mistress, who looks like a community theater version of Adrienne Barbeau (without the boobs or looks).
Again, there's spoilers, but it's from 1980, so if you don't want spoilers from there, tough (I won't say who shot JR though). Turns out Maude's nervous breakdown turned into full fledged insanity because Heather finds out that Grandma is talking as herself AND her long dead husband (whom she killed). Now I talk to myself on occasions, but I've stopped just short of axe murdering people...well outside of Des Moines...but they had it coming.
Here's the scene that convinced me she belonged on this list. It's really creepy how insane she looks arguing with herself. I just hope she can look at herselves in the morning.