Greetings, I decided to post this due to me finding out a thing last night in Zul'Gurub on the Zanzil Encounter. Hopefully this haven't been covered before, and if so I apologize. Either way
As you may have noticed when playing on your Death Knight we have the ability "Dark Simulacrum: Places a dark ward on an enemy that persists for 8 sec, triggering when the enemy next spends mana on a single-target spell, and allowing the Death Knight to unleash an exact duplicate of that spell."
The boss does Zanzil Fire during the encounter: "Deals 66000 Arcane damage in a line and deals 50000 Arcane damage every 1 sec for 5 sec." If you place Dark Simulacrum on him prior to him doing it, you can copy the attack and use it against him for easy Dps, Note: Your allies take damage from your fire aswell so be sure to tell them to watch out for both of them.
Just want to help share the info. Considering that he's one troublesome boss.
Hope it helps!