I've posted this elsewhere before, but it's definitely Pet Sematary for me, particularly the character of Zelda, still freaks me out now 20 odd years later, meaning I only watch it during the day
Don't know what it is about this scene that freaks me out so much, when I first read King's original novel at 11 years old, it didn't scare me all that much, but the following year when I rented the film with a mate(via his babysitter, who also rented us A Nightmare on Elm St the same night
), it scared the crap out of me and that first viewing has stuck with me ever since