The latest comic out (read it) has the new winner of the Best Expression Award. Originally it was held by the happy evil mage, but I think it has been dethroned by Cas Oh Crap Face:
It is a facial expression that speaks volumes. When I first read this panel, I initially thought it read like this:
It was only after careful examination that I realized that the dialog, in fact, was related to the smoke trail! I experimented with other dialog interactions, to see if this effect was persistent to all relevant scenarios involving duress:
I have thus found that the Cas Oh Crap Face is universal in saying "I am seeing something that is not within the bounds of comfort" and will supersede any text that is said at the time.