Shadow People, An analysis Options

I encountered what I presume to be "Shadow People" as a child, though as a scientist I'm inclined to believe I was hallucinating.

Has anyone here GENUINELY run into a full-fledged shadow person before? I'm looking for some answers regarding their motivations, origins and scope.

I'm going to have to say I've ran into a good few. I used to see them a lot as a child. The most terrifying memory I have of such a thing happened in the middle of the night oddly enough. I was asleep, but woke from some none specific unsettling dream. Nothing malevolent really, just uneasy. I knew something was watching me, something strange and alien and unknowable. I looked at the wall and there was a shape. It was darker than the darkness in my room and it had eyes. They seemed red. I closed my eyes and waited. The feeling remained, but I had hoped it was just my imagination. I opened them again and it was still there. Then it moved. I hid under the sheets for the rest of my life. I have a few more stories of varying amounts of fear, but from what I can tell they watch. They watch with a purpose that might be beyond human comprehension. I have a feeling it isn't good.