The Doomsday Weapon was a device created by the Uxarieans, capable of making stars go supernova. The Crab Nebula was formed when they tested it. Soon afterwards, radiation from the weapon’s power source began leaking, poisoning the soil on Uxarieus and causing the Uxarieans to mutate into three different species.
The Master stole the Time Lords’ file on the Doomsday Weapon and came to Uxarieus in search of it, hoping to use it to become rulerof the galaxy. However, the