I'm afraid to look outside windows at night. I guess some people are. It's just paranoia, right? You don't want to look outside your window at night and come face-to-face with an abhorrent creature. But, again, it's just paranoia, right? Too many scary movies, spending too much time on Creepypasta. Well, let me just tell you that you have a reason to be scared.
Occasionally you'll glance outside the window. You might want to know what the weather is like or you might have a completely different reason. Regardless of your reason, you're not expecting anybody to be standing on thin air outside your window. You look at your computer screen. It's getting late. It's just you and your friend at home. You look over at him and realize that he's fallen asleep already. You should go to sleep too but you want to spend a bit more time reading some creepypastas.
You see a shadow in your peripheral vision and immediately shift your eyes to the window. Nothing. You're relieved. You look back at your computer screen and hear a loud thud on your window. You shift your eyes to the window again; a bit more scared this time. You were right to be scared. You see your friend's body hanging outside your window. You're horrified. It's then that you realize that your friend was in his bed a few minutes ago.
You look over at his bed and see someone lying there. That's not your friend.