One of the scariest parts of both the book and the film adaption is Zelda's storyline. Rachel's handful of flashbacks — which include her older sister, who was plagued with a deforming case of spinal meningitis — are straight up chilling. And while it's terrifying enough that Zelda chokes and dies in the book, the movie's version where she dies after falling into a dumb-waiter shaft is even more frightening.