What I find slightly strange is that the loop-thingie is her spinal cord. Would her spinal cord not be in her back?
But, as I said before, awesomeness.
I was a bit surprised to see one of my fics on the front page again, seeing as I haven't updated either in so fliggin' long. I'm glad you enjoyed what I've written so far, at least. XD
As for Mewtwo's spine, she has this tube thing going from the base of her skull to right between her shoulder blades, and that's what contains the upper part of her spinal cord. Here's a picture of Sugimori's Mewtwo to show you what I'm talking about: