Xerogenesis is a mutagenic process caused by exposure to the Xerogen Mist created by the Xerogen Crystals. They were left by the Kree for Inhumans as a defense against the growing numbers of their human cousins. Whereas the Terrigen Mist enhances Inhumans with superpowers, the Xerogen Mists devolve humans into Alpha Primitives. The deposed Inhuman King called the Unspoken removed the crystals from Attilan. But when he was banished, he cultivated and grew the Xerogen Crystals.