The combination of man-made disasters and natural backlash - "green wave" virus leakage + global vegetation overgrowth disaster. A "plant activity enhancer" developed by a biological company was accidentally leaked and mutated into a "green tide" virus that can be transmitted through plant juices and pollen. The infected person will gradually become vegetative (skin grows moss, joints become stiff, and eventually become an immobile "vegetative"); at the same time, the virus accelerates the growth of vegetation around the world. Cities are swallowed up by vines, farmland is covered by giant weeds, and human living space is drastically compressed.
