[The fanfic of the 1958 version of The Fly. I can't remember the name of the protagonist and the specific content. You can also read it through an article that purely pays tribute to the 1958 version of The Fly.
[Landis is a scientist who has studied a method of transferring matter-splitting matter and then recombining it. Then when he was doing an experiment, he accidentally locked himself with a fly, and then exchanged heads and arms with the fly. When the human body still retained the remaining consciousness, he asked his wife to destroy the weird body that should not exist in the world, but the tiny fly was ignored and stayed. The story begins here...]