My family likes to hide and jump out to try to scare the bejeezus out of one another. It's a fun pass time :) So, about 3 or 4 years ago, when I was in the basement doing laundry, and I saw something out of the corner of my eye, I didnt think much of it, and braced myself for my son to jump out and scare me.
I should point out that my basement is completely open. It's not finished at all, so it's just a set of stairs (with open steps, as in, you can see through each tread), next to the laundry, and behind you when you are standing at the laundry is the hot water tank and furnace. Otherwise, everything else is just 4 cement walls.
So there I am at the washing machine, putting in a load, when I see movement at the right of me. That's where the stairs are too. I turned my head in time to see what I swore was the elbow of my then-10 or 11 year old son. It was white, bent at the elbow, and disappearing behind the hot water tank. I thought 'oh you little turd, how did you get down the stairs without me seeing you?' and I waited for him to scare me. I didnt want to disappoint him after he did so well sneaking past me on the stairs. I waiting a few seconds but nothing happened. I got bored, so thought I would scare the crap out of HIM instead. I snuck around the other side of the tank and furnace and found - NOTHING.
No one was there. I just about wet myself (seriously, it freaked me out totally), and I tossed the rest of the stuff in the washer, slammed down the lid, and ran up the stairs as fast as I could. The family were all where I left them - sitting together on the couch watching a movie. My bf saw the look on my face, and I was out of breath, and he said 'whats wrong with you?'.
I said 'oh nothing, someone was just trying to play hide and seek with me in the basement, and it wasnt any of you guys'. then I walked to the bedroom to calm down lol.
I dont know what I saw, but I have not seen it since. The pale white like my son's skin still stands out in my mind, at the right height for him at the time, the windows down there are very small and old, and do not face a street, etc. I wear glasses but I have for almost 30 years now so I am used to what I see as reflections and can normally figure that out instantly anyway.. this felt different. I was completely sure that my son was there to play our little game, and flipped out when he wasnt.