The Blue Ring is exactly what it sounds like: a blue ring of gargantuan size. If anybody tells you that there's a Red Ring, bigger than the Blue Rings, they're lying. There is no Red Ring. Don't believe them. Same goes for the people who believe that the Blue Ring is actually a triangle.
It is unknown if anything lies in the center of the blue ring, but at the current moment, no being has bothered to venture there. It is also rumored that the Blue Ring has the taste of blueberries and the smell of blue crayons, but this is unconfirmed.
Of course, the Blue Ring is truly nothing but another layer to this seemingly-endless wiki. Will it stop? Will it end? No one truly knows. But until we do find that answer, the least we can do is the time out of our day to admire this beautiful Blue Ring.
Note: Any attempts to eat the Blue Ring for their lunch will certainly be met with immediate obliteration. I'm looking at you, Tommy.