The Crispy Critters Act III challenge achievement says to "Use a Demon Forge to kill 3 Tormented Stingers at once".
I am assuming that the fire-breathing heads on the sides of the path in the last parts of Act III are Demon Forges.
Tormented Stingers are hard to come by in the last sections of Act III. Their non-achievement worthy cousins, the Stygian crawlers are quite prevalent. I only seem to spot Tormented stingers when they spawn surrounding a Hell Bringer Trap in groups of 6 or rarely from cocoons, 1 at a time.
Kiting these hard-to-find little pests is quite the pain as they pretty much die in one hit and often get too close when I'm stuck in the middle of a swarm of other mobs as I try to get them to what I assume are Demon Forges or get taken out by my follower before I can dismiss. Even when I get them there, they tend to circle around me which is no good as the assumed Demon Forges fire in a straight line with rather narrow spread, meaning that either some of them won't get hit or they won't all die at once.
I've been trying this as a Monk, but I'm considering the Demon Hunter's caltrops, assuming they don't kill the little crawlies. What is an effective strategy to getting this achievement? Are the things I assume to be Demon Forges, actually Demon Forges? Is there a more consistent location where I can get Tormented Stingers to spawn for this achievement? Is there a particular class/skill needed to do this successfully?