"Flowers for Algernon", or rather the second half of the story. It's a perfect window into what I think it would be like to have a degenerative neurological condition like Alzheimer's or dementia, and to be cognizant enough that you know you're losing your intellect and you can't stop it. That shit scares the f**k out of me, because it's a very real-life threat, and one of those things that's a personal nightmare of mine.
I never really thought the middle was scary, the end was disturbing as shit though. He knows that he used to be a genius, and was able to read the book (Treasure Island? my memory is fuzzy.). He knows that no matter how hard he tries, he will never be able to read it again.
The scariest thing I've ever seen would have to be Marble Hornets. I know it's not real, but it
scares the fuck out of me. There's one moment in particular, where Milo is sitting in the house. He points the camera out of the window, and Slendy Flies past the window and breaks into the house.
Tribe twelve has the one where Noah runs after his cousin and drops the camera in the house, and it
Centers on the slendy, as the camera fuzzes out.Moreso with SCP 106, or the grandfather. He's a
Half rotten man, who has the ability to teleport at will, and they can barely contain him. He takes his victims into a pocket-dimension, that contains his apartment. They never say what happens, as the entire thing is mostly [DATA REDACTED], but
This is a picture of an agent who was captured by 106.
He survived for one hour afterwards.