what are good horror or mystery books?
try Edgar Allen Poe short stories, they are a little hard read due to some tough vocab, but even middle schoolers an read it
How about you read some books by Stephen King, look them up.
As far as mystery goes, if you want something funny and entertaining, i recommend The Spellman Files by Lisa Lutz.
All Stephen king books and the book interview with a vampire
Try outpost it's kinda freaky
Miss Peregrines Home For Peculiar Children - Ransom Riggs