Search found 1 match: Vincent Price

Twin brother A is showing people around this Mansion, but people start dying. At some point they discover there's an empty dungeon in the Mansion. Twin brother A explains it was for his brother who was a deranged psychopath and he had to live in the dungeon since childhood - but now he's escaped!

I don't remember much else except at the end we find out the actual "nice" twin was killed long ago and this whole time the deranged psychopathic brother was the one showing people around the house.

There is a Simpson's Treehouse of Horror that was similar (Bart has a twin brother Hugo who lives in their attic and eats only fish heads) but Wikipedia doesn't credit any move as being the inspiration for that Simpson's episode.

I always thought it was a Vincent Price movie, something like House on Haunted Hill but it's definitely not that movie.

Any help or suggestions are appreciated!