"While I was out and about in Ponyville during the evening, I suddenly got attacked by a Wendigo spirit that intended to turn me into a mindless beast. But thankfully Twilight was not too far away to help me combat its evil influence as well as help me through the very painful transformation. I can feel that accursed Wendigo inside me, but it has lost so much energy in trying to influence me that it can't do anything now and it is stuck inside me. Surpisingly enough, I think this new form of mine can be extremely useful, sure my magical powers have decreased quite considerably but my physical strength as well as several other aspects have been greatly enhanced as a direct result of the possession attempt."
This was done as a Point Commission by  advanceddefense, who also by the way is in charge of the really good Tumblr comic Ask Twilight Sparkle/Werelight Shine that is about Twilight Sparkle's rival Trixie coming back to get her revenge by using the Wendigo spirits, here is the Tumblr itself:
http://twilightunbound.tumblr.com/