I wanted to do a butt-shot of Mist, and found a really sweet pose in a Playgirl magazine that I used as reference for it.  I was thinking of ways that I could justify the position he was in, tho, and while thinking about it I was reminded a lot of the way some anime character take on energy or magic attacks head-on, and thought, hey, it would be neat if he were taking an energy or magic attack head on, looking all nonchalant and unimpressed by the whole deal :)
