- King Aperture witnessing it
The Multi-Dimensional Fireball is a firey object that orbits the Universe. While orbiting, it may phase through multiple dimensions. The only point of intrest you may find on there is the current location of the Bureaucracy That Must Not Be Named. The last known sighting of the fireball close to the earth was on April 1st, 2004.
Aperture villagers believed that the MDF was made of plasma. It is also stated that the Fireball is a gateway to Purgatory and Afterworld. There are also legends of how the Multi-Dimensional Fireball was created, the most common one being that a ghostly ephyna drank syrup of ipecac, and the ipecac diseased the spirit, causing it to ralph a Multi-Dimensional Fireball . There are other legends, as well.