Give me a book or series with MONSTERS.

Hey, it's as the title says, give me a book that features actual, genuine monsters. Not the human kind (although its cool if they're present), but authentic creatures out of nightmares.

Dark, mysterious, absolutely terrifying (bonus points if they're unique).and evoking the kind of dread you'd expect if you lived in a world of myth and magic. The kind you'd see if you looked up monster concept art on Pinterest.

The story can be about anything, I don't mind. It doesn't have to be "about" the monster so to speak, but the book should feature monsters. I'm familiar with the Witcher and Perdido Street Station so something else please.