I've been living in the same house for three years, and seen some pretty weird stuff out of the corner of my eye, but nothing startled me as much as this.
When you first come into our house, there's the first big stairway maybe four or five feet away from the wall. On the first stair landing ,(there are three), there's this old gilt mirror about the size of a standard window. Well one Saturday night I was standing in front of the mirror fixing my hair when I noticed this male figure behind me. It was dark in color, but not exactly black, and looked like it was wearing a hood of some sort. There was a small yellowish point of light to the left which might've been an eye, and when you looked carefully, there was a darker shape like a cross over the other "eye", or where it should be, anyway. By the closeness of the reflection, he should've been standing right behind me. When I turned around, though, nothing was there.
The second experience was the one was freaked me out the most. I had just finished watching a scary movie, and was walking back upstairs with all my munchies and soda and, well, sugary loot. Just when I was walking past the landing, the same figure materialized in front of me. And 'materialized' isn't even the right word for it. It was more like not there one second, there the next. I just stared at it, my arms full of junk food. It didn't do anything at all for maybe half a minute, and then pointed at my house door and then "jumped" off the stairway. If you've ever seen someone bungee jump, it was a bit like that. It goes over, then it's dragged down so rapidly it's still kind of standing up. It must have fallen pretty fast, because when I looked over, (my mind hadn't gotten used to the fact this wasn't a real, living person yet, it wasn't there. Well, wasn't there completely. Part of a hand was pointing at my door, and when I went over to my door, it vanished. Though when I looked at my door, it was unlocked, and when I looked out the window in the door, there was this guy in a hoodie kind of prowling around my front yard like he wanted to come in but couldn't ask. I locked the door. Who knows what that guy might've done.