One great 'imdb two sentence horror stories' could be 'I woke up in the middle of the night. There was a figure standing at the foot of my bed with no face.' Another might be 'She heard a scratching at the window. When she looked out, a hand with long claws reached in.'
Well, 'imdb two sentence horror stories' often play on common fears. Take 'The phone rang at 3 am. No one was on the other end.' This taps into our fear of the unknown in the middle of the night. Also, they use vivid language in a short space. 'She felt a breath on her neck. It was ice - cold.' Just these two sentences can create a very creepy feeling as they quickly set a spooky scene.
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 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.
Some two - sentence horror stories are truly spine - chilling. For example, 'I woke up to a noise in the kitchen. When I got there, all the knives were floating.' The simplicity of the setting and the unexpected, supernatural element make it effective. Another one could be 'She heard a baby crying in the attic. She doesn't have a baby.' It plays on our primal fears of the unknown and the unexpected in a very short space, creating a sense of unease and horror.