Infinity Big Bang Storm

Infinity Big Bang Storm is the name of the most powerful attack thrown by the Gunmen the Anti-Spirals created, Granzeboma, to anniihilate Tengen Toppa Gurren Lagann down to its very last scrap of DNA. 

The mech grabs two nearby Super Spiral galaxies in the Super Spiral Space, crushes them together, and compresses their matter and energy into a ball. It then unleashes the resulting pressure, combined with the Anti-Spiral's own energy, as an enormous blast of raw energy. As the name implies, it is a wave attack that consists of an everlasting Big Bang-like energy blast. As the Tengen Toppa Gurren Lagann is shielded from this by Lazengann, new Super Spiral galaxies can be seen being born endlessly as a result of this energy being unleashed.

Power
Infinity Big Bang Storm has the power on par with the creation of the entire universe (the entire existence) with endless series of Super Spiral galaxies literally flying from the point of impact. The blast is able destroy opponents at the quantum level and greatly struggles Tengen Toppa Gurren Lagann, a mech possesses the the Multiverse Labyrinth and Super Spiral Space within itself.

Trivia

 * "The Universe" in this context shouldn't be mistaken as a (one) regular universe, "Universe" as said by Nakashima could be described as a universe full of universes with all kinds of possibilities. Wikipedia as well stated it can be defined as "the totality of existence", or everything that exists, everything that has existed, and everything that will exist (Applies to Spiral Nemesis as well). So not only this attack was made in 11 dimensional space, it also supposed to be on par with the entire possible existence. It shouldn't be taken as a (one) regular universe or it'll be extremely contradictory with the power scaling.