Infinity Big Bang Storm

Infinity Big Bang Storm was the declared name of the most powerful attack unleashed by the strongest Gunmen the Anti-Spirals summoned, the Granzeboma.

The mech grabs two nearby galaxies in the Anti-Spiral dimension, 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, equivelent to the energy of multiple Big Bang explosions; as Tengen Toppa Gurren Lagann is shielded from this by Lazengann, new galaxies can be seen being born as a result of this energy being unleashed.

Power
The Anti-Spiral states that the Infinity Big Bang Storm has the power to create and destroy entire universes. The name implies that it has the power of multiple Big Bang explosions.

In Gurren Lagann The Movie: The Lights in the Sky are Stars, absorbing the Infinity Big Bang Storm allows the Tengen Toppa Gurren Lagann to transform into the Super Tengen Toppa Gurren Lagann, which has 57% the size of a single universe; the Anti-Spiral dimension is hundreds of times larger, thus it has an omniversal size equivalent to thousands of universes. Since the Super Tengen Toppa has enough power to destroy thousands of universes, this would indicate the Infinity Big Bang Storm is similarly powerful.