The Fly (1958)

At the behest of his distraught sister-in-law, Helene, industrialist François Delambre finds himself entangled in a macabre confession: she has murdered her husband. Initially resistant, Helene divulges the extraordinary circumstances surrounding her desperate act, ultimately revealing to the authorities the genesis of her husband's fatal experiment. He, a brilliant scientist, had pioneered a revolutionary matter transportation device. Tragically, hubris and a common housefly conspired during a self-test, resulting in an unforeseen and horrific metamorphosis. The consequences of this fateful incident irrevocably altered their lives forever.