Well after much effort i (95 Warrior) finally finished this mob off (last one i needed for hunter achievement). I took the advise of the below comment. its partially true, yes keep your DPS LOW, but as a warrior i was unable to turn my attack on, as i DPS more than that. i just stood at the mob with attack off, taunting and keeping my ac up with my discs, while my 90 necro's pet pounded away on it. i tried to use a 84 warrior merc. it died right away. It was a LONG fight but seemed to work. at about 40% mob does start to cast the Corrosive Pollen, but with 3 healer merc's (lvl's90, 94 and 95) no one died. i did periodically life tap with necro. at about 20% i laid on every dot i had memorized. and it died very quickly after that. Hope this helps!
Gig

Diamond
Distilled Grade C Gormar Venom
Dream Dust
Elegant Adept's Shard
Empyrean Hammer
Glowing Nebulous Dream Fragment
Greater Nebulous Dream Fragment
Lesser Nebulous Dream Fragment
Median Nebulous Dream Fragment
Minor Nebulous Dream Fragment
Recondite Remnant of Truth
Tantalum Ore
Visage of the Sinister Drone
Zonoraz' Impaler
