I guess this is another post of yours, wanting me to stop making up theories again as you implied.
Smudge from where? The shoulder doesn't seem to be a pillar because a pillar isn't supposed to be a round. If it was a smudge, it would be very visible very next to the area of a thing. The zack's shoulder substance is white, and the wall is black, most of them are grey, so it can't be a smudge either.
Like I said, if I was sure that it was probably nothing then I would have never made this thread in the first place.
o_O
http://img187.imageshack.us/img187/9738/huh2bf2.png
Assuming the grey wolf is a represention of Zack.
Maybe it was that same grey wolf (inside that circle) with Zack on the top of it