Space

All right, but your mom is a close second.

Apparently Quipu is a superstructure containing 200 quadrillion solar masses. From the article: "Superstructures are extremely large structures that contain groups of galaxy clusters and superclusters. They're so massive they challenge our understanding of how our Universe evolved. Some of them are so massive they break our models of cosmological evolution.

Quipu is the largest structure we've ever found in the Universe. It and the other four superstructures the researchers found contain 45 percent of the galaxy clusters, 30 percent of the galaxies, 25 percent of the matter, and occupy a volume fraction of 13 percent."

Getting pretty generous with what we call a "thing" there

Something something... your mom.

Is the white outlined part in the first image and the black part in the purple-yellow image the part of the universe we can't see because the Milky Way is in the way?

This is fundamentally stupid.