"Non-Euclidean" is a term taken from David Morgan-Mar's Irregular Webcomic, I believe. I can't think of anything else I'd be reading in 2008 that'd have the term in it.

Irregular Webcomic influenced me quite a bit as well, if these annotations are anything to go by. So with that in mind, I'd like to see if I can't deconstruct the use of "Non-Euclidean" in this strip.

As I understand it, it works like this: Euclidean geometry is the basic 2D geometry you learn in geometry class. The sum of all the angles on a triangle is 180, that kind of shit. In non-euclidean geometry, if you laid that same triangle on the surface of a sphere, the sum of the angles wouldn't equal 180 due to the distortion caused by the curvature. This is an oversimplification but it's more or less the gist of it.

David used this when referring to Cthulhu as a shorthand way of saying he's not of this Earth, and rightly so, as he was directly referencing H.P. Lovecraft's own description. He defies normal 2D geometry, and obeys his own set of strange alien rules. If you laid a triangle on Cthulhu, the sum of its angles would equal something weird like Pi.

Since there's no way 2008 me could have comprehended this, it's safe to assume Chaos here is saying something ridiculous like "I am three dimensional!" Or "I have a gravitational field!"