Kanske Martian , från Ray Bradbury's The Martian Chronicles , (1950).
LaFarge and his wife Anna have forged a new life for themselves, but they still miss their dead son Tom. A night thunderstorm startles the elderly pair, who see a figure standing outside their home in the rain. Afraid, Anna goes to bed, while LaFarge believes that somehow Tom is standing before him. He leaves his house unlocked.
When morning comes, "Tom" is busy helping Anna with chores. LaFarge sees that Anna is somehow unaware of Tom's death, and after speaking privately with him, LaFarge learns that "Tom" is a Martian with an empathic shapeshifting ability: the Martian appears as their dead son to them.
Later that day, Anna insists on a visit to the town. "Tom" is deathly afraid of being so close to so many people. LaFarge promises to keep him close, but at the town they become separated. While searching for "Tom", LaFarge hears that the Spaulding family in town has miraculously found their lost daughter Lavinia. Desperate to avoid a second devastating heartbreak to his wife, LaFarge stands outside Spaulding's home and finds "Tom" now masquerading as Lavinia. He is able to coax "Tom" to come back, and they run desperately back for their boat to leave town. However, everyone "Tom" passes sees a person of their own—a lost husband, a son, a criminal. The Martian, exhausted from his constant shape-changing, spasms, and dies.