Maurisuvius (the Purple End of the World)

The Maurisuvius Rift is a space-time rift that first appears near the end of season 4 and ultimately destroys the world a few episodes later. The rift appears as a hole in the sky that emits staticky purple light, earing the nickname "the Purple End of the World".

Origin
Maurisuvius was created by the CIA's attempt to dismantle the Maudling's Apex Device during Operation Calico. CIA Agent Jack Turner attempts to disable the device as instructed by CIA Agent Claire Madison. Instead of rendering the device inoperable, he triggers a reaction which fires a beam of purple light into the sky, vaporizing himself in the process.

Destruction of the World
After spreading across the sky for several days, the rift grows to block out the sun and stars, freezing all time-keeping devices and eliminating any sense of night or day. During this period, Agent Claire Madison and Ericka Keane use their combined knowledge from their Omphalos visions to ascertain that there will be a cataclysmic event if Maurisuvius reaches critical mass. Based on this information, the CIA begins to implement the Flashbulb Initiative in order to save the town, but it is implied that the Initiative is only partially complete by the time the rift destroys the world/television show at the end of season 4.