The novel Little Mushroom was first published by Shi Sizhou in Jinjiang Literature City. The main content is that the geomagnetic field will disappear on the earth in the future, cosmic radiation will cause great variation of global species, the biological gene combination will be completely broken, and the genetic competition between different species will continue. In this mutation, which seems to be driven by a huge force, the human species has completely fallen from the top of the biological chain, and human genes have targeted other species, making it easy to be infected and become heterogeneous. In order to protect and continue human civilization, human beings have built four human bases around the world and two artificial magnetic poles in the east and west to replace the disappearing geomagnetism. Survivors linger in the last days, and the flame of civilization flashes faintly in the stormy. In this context, the protagonist, a weak little mushroom "alien" infected by human genes, came to the northern base of human life to look for his lost spores. At the gate of the base, he met the fate judge Lu As, and the story of the weakest alien in history and the strongest human guardian who specializes in killing aliens began.