The Eye of Disharmony was a superweapon created by the Threshold in the town of Wormwood on the Moon in the 53rd century. It had the appearance of an upside-down, four-sided pyramid with an eye on it.
The Threshold activated it and "destroyed outer space". The blackness of the universe became white and all ships that were not within a planet's atmosphere at the time of activation were destroyed. The Threshold planned to sell transportation to the universe, but the Eighth Doctor defeated them, and space was reverted back to normal, destroying the Moon in the process. (COMIC: Wormwood)