Not exactly what you're looking for but many years ago I had a brief encounter in the TV industry and the talent looked so different IRL it was spooky. Very skeletal, bony, with sharp angles and much smaller in stature than you would think. In person, they looked like they were sick but on the screen and tabloids, they were depicted as "heart-throbs".
I've also met a few incarcerated people who were "off" with charges that stood out in their cruelty/callousness. One had put CLR-away in his grandma's eye drops. When you spoke with them, they desperately tried to appear normal but the coldness in their eyes and sinister smile made my skin crawl. Not exactly the alien/robot story you're looking for but nevertheless inhuman and disturbing.
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