Anti-Matter Cannon
From Multiversal Omnipedia
The anti-matter cannon was a massive weapon constructed by the Thunderers of Qward for the Anti-Monitor. It was intended to destroy the remains of the positive matter multiverse, but it was destroyed by a self-sacrificing Flash.
Alternate Timelines
In an alternate timeline where the second Flash was slain early by Cobalt Blue, the anti-matter cannon was not destroyed. Although many of the positive-matter heroes survived to battle the Anti-Monitor, the balance between positive and anti-matter was so weighed in his favor that he was practically unbeatable. The original timeline was restored by the third Flash.
