Cancer Void is a completely white void that when traversed at 5,000,000,000,000 - 6,000,000,000,000 kilometers (or 5 petameters to 6 petameters) per second will rupture and allow you to achieve unheard of acts of power, some of which include, altering the past and creating and alternate timeline and merging those two together, nearly destroying the entirety of something truly endless, holding the beliefs and thoughts of every conscious being in existence in the palm of your hand, and possibly even reaching outside the known hierarchy.
This dimension is also known as a "physical dream" because of its quite strange reactions to thoughts. There are things in this dimension, they are spaced about 99999^9999999^99^9999^9999999^9^9^99 light years apart each and they are the size of a grain of sand, but they have the mass of seven universes.