Nibiru is a legend well-known in Babylonian history. It tells the story of how a large object, either a planet known as Twelfth Planet, Planet X or Nibiru, will collide with Earth. It is referenced as "The Doomsday Event". In this event, god-like creatures on the planet Nibiru will arrive on Earth. One known sentient of the planet was captured inside a sarcophagus. A planispheric disk was created in order to make the treasure hard to find, first created by the Conquistadors who realised the power of the god inside. It appeared in the second season of The Powerpuff Girls Crossover.