Detail from a painting of the Lady of Shalott by John William Waterhouse.
I have not been sleeping well lately. I suspect that the reason is related to my new bed (could it be too comfortable?), although I am not entirely sure. One disturbing side-effect is the shadows I have been seeing lately.

They have occasionally happened before, although never with this frequency (once every couple of hours). Normally, it is the impression of some quick movement that appears at the very edge of my field of vision that does not resolve itself into anything real when I stop to look and listen. At its most material, I saw what I could only describe as a large floating black handkerchief reflected in a mirror in my bedroom. Since the area of wood floor where it appeared in the mirror is also in sight, I know that it did not exist, but such knowledge does not make me feel any better.

if this was a horror movie, the Evil would appear and take me away right after I pressed the "Publish" button, leaving my last words as a vague but telling warning about my disappearance. The police would dismiss it, but you, my readers, would know better.