Heiho,
there are several factors which make them little buggers dangerous. Maybe some collected information give you a little help here.
Base life of the three subclasses is avg~800 in Hell.
Their explosion damage is roughly about 10-12% of their former life points. It is nearly absolute sure that without boss enchantments the explosion is 100% physical damage.
The ability of doing a Critical Hit seems to be applicated also to the exploding 'attack'.
The life points scale with player number as follows
1ppl 100%
2ppl 200%
3ppl 300%
4ppl 375%
5ppl 450%
6ppl 525%
7ppl 575%
8ppl 625%
Life points of Champions (not all subclasses) are increased by 400%
Life points of specials (unique monsters) are increased by 800%
Life points of Minions of a bosspack are increased by 200%
Cold enchanted will add a kind of Frost Nova when dying with damage ~ 4 * [mlvl / 2]
Fire enchanted will add a fire damage from 7,5 up to 10% of former hitpoints
If a unique doll explodes and had cursed or convicted you before, these will modify your received damage the usual way (note, Conviction by monster bosses is sLvl=mLvl/4)
[color=red]
What does _not_ add to the final explosion are modificators like
Might
Fana
extra fast/strong
Spectral Hit (not sure here)
Stone Skin
Teleportation
Magic Resist
Mana Burn[/color]
An example
unique doll, Hell, 8ppl, no enchantments, no aura, no curse
33550-55250 HPs
3350-6630 physical exploding damage
5% chance to do a Critical Hit
6700-13260 physical exploding damage
In general you can only work with four tactics vs dolls
a) high block, high def, with the remaining risc
b) damred (in % if available), also with remaining risc
c) ranged attacks, which are not possible with every build (and because of the dolls being really fast and hard to aim it is still a risc ...)
d) let your hireling/minions finish them and stay out of the way (and there is still risc ...)
<edit>
typo, and inserted an example, hopefully a good one
<edit#2>
HPs of Minions added
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