Book(s) that left you feeling uneasy, frightened, disturbed etc

I posted this in the r/Recommend_A_Book subreddit & got some wonderful comments, so I figured I'd post it here too. 🙂

A book that scared or creeped you out – from spooky to disturbing and anything in between. A book that you couldn't stop thinking about. A book that stayed with you.

Thanks!!❤️