Flies is a science-fiction short story by Isaac Asimov.
A standalone story, it was first published in the June 1953 issue of The Magazine of Fantasy and Science Fiction. It was later collected in 1969's Nightfall and Other Stories.
Summary[]
At a college reunion twenty years after graduation, a group of friends discusses their lives and careers. Among them is an animal behaviorist who has developed a heightened, almost painful sensitivity to the subconscious cues and minor behavioral tics of those around him, allowing him to perceive their hidden thoughts and insecurities.
His attention is drawn to another friend, a chemist who has become wealthy by developing a powerful insecticide. Throughout the reunion, the chemist is persistently plagued by flies. The behaviorist, interpreting the insects' actions through his unique understanding, realizes the horrifying truth: the flies are instinctively swarming around the chemist because, on a primordial level, they recognize him as their destroyer—a modern incarnation of Beelzebub, the "Lord of the Flies." This grim insight underscores the story's meditation on unintended consequences and the hidden burdens of success.