I have many PowerAuras for Firelands bosses in the sticky here:
http://www.mmo-champion.com/threads/...aid-Bosses-PvP
We are probably going to work on Beth Heroic next week but from reading several World of Logs and watching that video it looked like that was the
Cinderweb Drone that was fixating on the tank when he jumped out. I don't see any reason for that unless the person being fixated on is near the Cinderweb Spiderlings to begin with.
The mob to worry about is the
Engorged Broodling. I don't think the Broodling actually puts up a Fixate debuff, but that's the one you need to look out for and get out of the raid with. I have a Fixate PowerAura in the link. Volatile Burst doesn't look like an buff\debuff aura, it's just the spell that's cast as he touches you so I think that's the wrong aura.