Cadaver Bear, but debatably even more painful. He does a few million damage per hit while taking his Scorching damage into account

Note: Scorching is an effect that deals damage to those inflicted with the effect every second/30f
The damage is equal to x% of the original attack's damage, the level of Scorching decides the percentage, starting at 10% at level 1, 20% at level 2, 30% at level 3, and so on