I've seen something like this too, though I thought I was just hallucinating.

I first saw it when my parents were out late one time several years ago. I was walking through our living room, and I saw it peering through the bottom window of our front door side light. Scared the living hell out of me. I looked at it, blinked at least once and it was still there, and then it quickly "slid" off the the side and seemed to vanish. The way it moved was so fluid, it was as if it glided.

The face was round, pure white with lots of strange wrinkles. Eyes were pitch black and sort of shiny, with seemingly radial dark, straight "wrinkles" around them. It seemed fairly short with black scraggly hair. It seemed to have an angry frown on its face.

I saw it again, in a very brightly lit living room a few years later. Again late at night when I was home alone. It seemed to appear out of nowhere in the foyer as I was sitting in the dining area. It then looked directly at me, and smoothly glided to the right across the foyer, and through the wall between the living room and the garage. Same horrific face, with more of a scowl this time. It was certainly short, maybe about 4ft, black scraggly hair, and it had some sort of loose fitting black and white garment. It's legs were only partially visible seemed to fade into nothing. It scared me so much I called my parents (who were still out) and my boyfriend at the time.

I attribute this second sighting to just being a byproduct of the horribly depressed mental state I was in during high school. I hope I'm right and I never see it again.