Let my Gale origin Tav sneak up on the rafters of Razglin's chamber to pelt the goblins from above with spells.

One of the goblins threw a void bulb in my direction, which hurled Gale down from the rafters. To the floor ? No, not to the floor but right into the hole in the floor that drops into the spider's tunnel.
58 bludgeoning damage from one goblin attack. (Gale had something like 30 in total. It felt not good)
As it was my Tav origin, I couldn't leave him there to have him resurrected by Withers later. So my party had to try to get him out of that spiderpit while fighting Razglin.

Fortunately, the party was composed of 6, so I could get Wyll to misty step and aid "pancake" Gale and keep the spiders at bay .

void bulb can be really impressive. It's fortunate for us that the enemies don't always use theirs immediately against us to sew chaos and confusion.

I usually hoard mine for the temple of Bhaal where I use them to suck the praying Bhaalists who are protected with sanctuary in a heap to give them some fireballs and icestorms afterwards.