Excelio Variable Gravity Well from Gunbuster: a planet-sized monster that crawled out of a Black hole, and now drags around the black hole as a weapon:
From Gunbuster, particularly the 2004 sequel.
I love my esoteric and powerful creatures, and this thing fits. First, yes, it's the origin of Ramiel's screams from Evangelion, it was made by the same studio before it. It is the result of a black hole sucking in a fleet of hundreds of millions of space-monsters, that then merged into one inside the black hole, and crawled out of it, and now uses the black hole as a weapon. At 12,000km, growing to 30,000km long, the size of a planet.
I love how the black hole is incorperated into the design, like an omnious Halo behind it's head. I like the multicolored scheme, giving it an alien feel rather than a block of grey. I like hwo the colors darken as it devolves, and finally the 3 eyes that emerge are amazing.