Most lethal champion attribute you've encountered?

As the topic states, what's the most dangerous attribute you've encountered on a champion pack so far?

After about 15 playthroughs I hit a champion earlier in the 2nd level of the Den of the Fallen with a 'Molten' attribute -- the pack left a trail of lava wherever they went that does quite a bit of damage (my lvl 9 Sorc almost died to it in HC) and when the pack boss dies he explodes dealing huge damage (half my Sorc's life).

So far this has definitely been the most lethal-seeming attribute I've encountered, one of the few times in the beta I almost had a character die.