YES

From The Comics Reporter:

"...Were you aware that Lewis Trondheim did a signing where he set one of his sketches on fire? I heard about this and CR reader Jeremy Stone confirmed:

I was standing in line behind a woman who got a copy of Dungeon signed and she asked for a sketch of Marvin breathing fire in it. Trondheim drew Marvin in the corner of the first page with the fire line spreading out, then lit the corner on fire, let it burn to his inkline, and threw it on the floor, closing it to put out the flames. I wish that I had my camera ready, because it was awesome, and it turned out great. I should have at least taken a picture of the finished product, but I was too awestruck.

I mean, if nothing else happened this year, Trondheim using fire as an impromptu illustrative tool happened. Isn't that cool?"

UPDATE: Now with pictures! (via the daily crosshatch)