You know what an Ultimate Nullifier is--you've held one in your hands... This? This is its monstrous mother--a nameless entropic nightmare. A universe killer...and a universe creator. 
History
This nameless Celestial device was stolen by Galactus, who had gone mad and planned to use it to reset the universe. The machine was destroyed by Valeria Richards and H.E.R.B.I.E., but they sacrificed themselves in the process.[1]
Properties
Doctor Doom compares this machine to the Ultimate Nullifier, calling it the Ultimate Nullifier's "monstrous mother." Not only is it a universe killer, it is also a universe creator. The machine requires an immense amount of energy to activate, and Galactus planned on using the energy he had gathered from countless devoured planets. Once it is active, it cannot be disarmed, except from the inside.[1]