I don't remember exactly when my story took place. However, it happened in our old apartment in East of Sweden. We moved from that apartment when my brother was 4, so I was younger than 11 then. I'd imagine about 9.
To paint a scenario for you, it was just like any normal evening, and since I'm so fond of composing stuff, I was writing by my desk. Not once did I look back, why would I anyway? Why and how could anyone be behind me, if you understand what I mean? I got bored of writing after a while. I can't tell if it was warm or cold in the room, since this was so long ago. I got up from my quite comfy chair and took a step back, to push in my chair, just like I usually do. Then, I swear, it felt like I bumped into someone's back. You know when two people with their backs against each other collide? That's what I felt. It was just plain reflex to look back then, even if it was impossible for anyone to sneak in unnoticed. My desk was, after all, just next to the door. When I looked back, to my horror, there was nothing or no one there. I remember it terrified me a lot. Who wouldn't react that way?
I don't want to hear again that I imagined it, because I know what I felt, and I swear, I bumped into someone.
If you have any comments regarding this, let me know.