The main character's insane elderly mother from Braindead. Fucking hysterical. She's chewing the scenery with all of her might and its a genuine spectacle.
Unironically this. The script was passed on by a bunch of people because they didn't know how to play the character and he committed to it and it rocketed him to super stardom. He offered to do dumb and dumber for really cheap and they didn't want him, then this became a huge hit and they had to pay him like 20 times his original asking price about a week later to play Lloyd Christmas.