Whether you were 8 years old or a grown adult the first time you watched Alien, you're probably still a little unnerved by mealtime coughing fits. And if you've seen The Sixth Sense, the image of the ghost child throwing up in Cole's bedroom fort is something you won't soon forget. Even modern horror can evoke a sense of unfettered disgust seared into your memory for better or for worse - Charlie's severed head in Hereditary, for example, is both tragic and terrifying.
Horror fans know that the most gruesome scenes in horror movies are not something you just let go of. These are the scenes between those rare moments of levity, and part of the fun of being a horror fan is filling your mind with disturbing imagery and seeing how long it takes for you to fall asleep. If nothing else, these creepy horror movie moments sure make for some cinematic nightmares.