<snip> the smoke and gasses produced from an arcing cap can conduct electricity so just getting close, or into the smoke, my be all it took to get a fat discharge. Ever try a Tesla coil in a smoke filled room? You may have to tune it a little but it seems more violent or maybe it was the excitement of one of the caps exploding, not sure, that was ten years ago. <snip> It might have something to do with the type of smoke ;)