Alien brain-eating spores have arrived on Earth and have been quietly lurking for fifteen years.
Over the past fifteen years, the spores have spread silently through the air and water, parasitizing humans and devouring the host's brain, perfectly replicating the host's appearance, voice, memory, and behavioral habits, transforming into a human, and completely integrating into human society. The whole world seems to be peaceful and normal, the cities are in order, and the people know nothing about the existence of the parasite. Sporadic disappearances and bizarre deaths over the years have all been officially classified as accidents, homicides, and missing persons, and the truth has never been revealed.
The parasite group has long formed a stable hidden ecology: no active killing, no identity exposure, low-key dormancy, secret eating, and slow advancement. The weak and the strong eat among the same kind, but maintain a delicate balance of survival. There has been no large-scale crisis in the past fifteen years, and high-level parasites are hidden so deeply that almost no one knows their existence.
