Wiki:

The Medea hypothesis is a term coined by paleontologist Peter Ward for the anti-Gaian hypothesis that multicellular life, understood as a superorganism, is suicidal; in this view microbial-triggered mass extinctions are attempts to return the Earth to the microbial dominated state it has been for most of its history. It is named after the mythological Medea, who killed her own children. Medea represents the Earth, and her children are multicellular life.