Any horror sub-genres we've never seen?

I was trying to think of various horror sub-genres that no one has ever made (or, at least, that I'm unaware of...).

Which horror sub-genres have you never seen or heard of?

And if someone posts a horror sub-genre they've never seen, and you can think of an example of it, feel free to comment and let them know!

Mine would be:

Gangster Horror: I've never seen a horror film in a classic Mafia / gangster setting a la The Godfather or Goodfellas.