Unexpected return of an old ghostly friend

So I was outside a familiar door recently, closing it. Looking at the glass in the door at my reflection I noticed a dark figure just behind me. I could only see a small part of the figure as it was mostly obscured by me! As anyone who watches detective TV shows or horror movies knows, this is never a good situation! I swung round immediately only to see absolutely no one there. There is no cover anywhere nearby so no one could have run away fast enough to not be visible in the tiny time it took me to turn round. So, a ghost then.

Long time readers will remember the door ghost. This is indeed the same door but the door ghost hasn’t appeared for years now. Furthermore, there is a notable difference to the old apparition. The original door ghost was low down - this ghost was over my shoulder. They were similar, however, in both being all dark. The original ghost was a peripheral vision misperception of my own arm and hand. This time I think it is a misperception of my hair. I should explain to the incredulous that I have for a few years now (all after the original door ghost) had long hair going down below my shoulder. So why don’t I see this new version regularly? Well, the hair is mostly well behaved but rarely it can 'pile up' on one side.

So to see this new version of the door ghost I need an unusually bad hair day plus looking at just the right angle at the door window. I think those factors only coincide very rarely. Incidentally, this makes me wonder how often witnesses omit important details from their reports due to embarrassment?