Okay, here is another mysterious photo I took at the same Halloween yard haunt that I took the other photo at.
Look to the right of the prop monk, just under the tree branches and behind the small white fence.
I see a white hooded "thing." When I went to this show, I would hang around for a long time observing and taking photos and I didn't see anyone in a costume like that in the photo. Also, it would have been a very poor mask; look at the way the chin juts out. Maybe it's just some ghoul saying hello to his "friends" (the props)!