Phazon is a highly radioactive substance originating from the living planet known as Phaaze, known for its extreme mutagenic and energy-producing properties. Strangely, it's not only a radioactive substance, but also an extradimensional living being. Phazon appears throughout the Prime Trilogy. The substance has been responsible for the near-destruction of two worlds, Tallon IV of the Chozo and Aether of the Luminoth. In both cases Phazon arrived on the planets via interstellar objects, now known to be Leviathans. On Tallon IV the Phazon devastated and poisoned the ecosystem, eventually destroying the Chozo society that existed there. In Aether, the Phazon Meteor struck the planet and split it into two dimensions, driving the planet and its inhabitants into turmoil.