“Windeye” by Brian Evenson.
I can still vividly remember hearing Evenson read this story (also the title story of his excellent recent collection, via Coffee House) at the 510 in Baltimore and gasping at a certain moment, when the terms change radically (you will know the moment when it arrives). A spooky, weird, haunting story about the confounding, multifarious nature of reality (among other things). I still think about this story A LOT, which is probably why I teach it (and often the opening paragraphs specifically, for a craft talk I do on story openings) so much. Here’s the first paragraph: