Phazon is a substance of extragalactic origin. It is a highly radioactive ore with extreme mutagenic properties. It has certain biological qualities, including the ability to reproduce itself. Exposure to Phazon often affects the brains of sentient beings, causing erratic, destructive behavior. It is also a potent source of energy, surpassing even Fuel Gel in pure output potential. It must be handled carefully, as it can cause "Phazon sickness" if used incorrectly.