Shadow person. It was walking down the hallway where I just was, heading for a defunct door that I now know just led outside. I called out to it "hey, wait!" with no fear for a pipsqueak. It stopped walking for a moment and I could feel it looking at me, despite having no eyes, then it continued on.

At the time, I didn't know where the door led, all I knew is that my mother told me to stay away from it. After the experience with the shadow person, I believed it to be a doorway to the afterlife, at least until a couple years later when I found out it just went outside.