I would be grateful forever to anyone who can tell me the title or author of a story I read when I was a kid in the 1970s or very early 80s. It was only a few pages long and described a soldier stalking an "alien" enemy whom he finds repulsive. He eventually shoots and kills him and when he goes up to the body his description of it causes the reader to realize that the "alien" is actually a human. I've been googling for hours to no avail. It would have been in a short story collection from my school library.