I feel like the reverse situation kinda writes itself as a sci-fi horror short story: You've got people living their every day lives, when a probe from space l

I feel like the reverse situation kinda writes itself as a sci-fi horror short story: You've got people living their every day lives, when a probe from space lands and starts producing aliens. At first it's treated as a strange curiosity, but with time the aliens begin to make inroads conquering the planet. Ending twist: the aliens are humans, and the "people" were aliens!