The old house was said to be haunted. I didn't believe it until I saw the door slowly creak open on its own.
I woke up in the middle of the night to a strange noise. When I turned on the light, there was a shadowy figure at the foot of my bed.
I saw a figure at the end of the hall. As I blinked, it vanished, leaving only a chill.
Another really scary one could be 'My phone rang at 3 am. The caller ID said it was me.' It plays on the idea of the self being something other or unknown, and calls at that time are always spooky.
I was alone in the school gym. A cold hand touched my shoulder, but when I turned, there was no one there.
She checked under her bed. A pair of eyes stared back.
I woke up to the sound of scratching at my window. When I opened my eyes, a shadowy figure was peering in.
Well, there's 'My daughter won't stop crying and screaming in the middle of the night. I visited her grave yesterday.' Also, 'I heard a noise from the basement. The power has been out for days so it couldn't be the furnace.'
I think 'The clock stopped at midnight. Then I heard footsteps.' is quite scary. It gives this feeling of something ominous starting right at a spooky time.
I think 'I heard a child crying in the basement. But I live alone.' is quite terrifying. The idea of a crying child in a place where no child should be, especially when you live alone, plays on our fears of the unknown and the supernatural. It makes you wonder what could be down there, and the thought that it's not a normal, explainable situation is very frightening.
My reflection waved at me. This is extremely creepy because our reflection is supposed to be just that - a reflection. When it takes on a life of its own and waves, it shatters the normal perception we have of ourselves in the mirror. It makes you question what is really on the other side of the mirror, as if there is an alternate and perhaps malevolent version of you.
Sure. 'I found a doll in the attic. At night, it moved on its own.' Dolls are often creepy, and the thought of one moving by itself at night is really scary.