Abaddon (Fire and Brimstone)

Abaddon was a potential destruction for all of Creation: the collapse of all possible universes into a single hellish whole.

Ptolemy Muttonchops, the avatar of Crivello's Cauldron, had a vision in the Gazing-Pool of Abaddon being heralded by the Black Sun as demons swarmed out. This vision was later realised by the collapse of the Cauldron itself by the Dalek Hive into a black hole and interdimensional gateway, out of which Great Vampires and monstrous alternative Daleks began swarming out. While the collapse of possible universes began as a result of the wormhole's opening, it was averted when the Eighth Doctor and Muttonchops managed to make the black hole go supernova, destroying the Daleks and Vampires and sealing the rift. (COMIC: Fire and Brimstone)