Or "Abstract Art of the Luna Arena", would you believe - and don't worry, I've made Icedude
promise not to do it again!
This is very difficult to rate, but, intriguing though it is, it must have been a lot less work than the simplest new map or remix. All the 'Dude did, basically, is take Luna Arena and turn it upside-down! The playability is not great, though it is fun to explore or fool around in - there is "clipping", and stuff that appears and disappears depending on your angle of view - it is also pretty easy to fall out of the bottom (top?) to a swift but painful death...
This map comes as part of Icedude's map pack, along with Circular Forts Stadium and EZDM, which are a bit more conventional!