Spore Loser (10 player)

I'm writing here a short list of buffs / spells you shall not use, which caused us to fail.

DK: Obviously, pestilence and all that AoE stuff. Just to remember, Wandering Plague will cause the spores to die. Also avoid Army of the Dead.
Mages: Molten armor. yes, the spore may try to hit you and die if it crits (+ignite = death!). Mirror image is also a menace.
Druids: Thorns. Don't use it!
Warriors: Please, if you're not the only tank, then remove your shield, because the damage return kills spores too!
Warlock: Imp's Fire Shield!
Hunter: check your pet for aoe moves (thunderstomp, swipe, flame breath or whatever)
Paladins: Retribution aura, divine storm
Shamans: Chain Lightning, Searing totem (yes!) and lightning shield
Priest: none observed. Be cautious with shadowfiend though.
Rogues: Blade Flurry, Fan of Knives and Killing Spree.

I'll add up as I remember / get told about more spells. Hope it helps avoiding some frustrating attempts!

This achievement has been confirmed as fixed as of patch 3.0.8. Did this tonight on 10-man, simply ignored the spores, who seemed to just chip away (barely) at the healers. Very easy achievement.

If you are trying this achievement in Mists of Pandaria and are using [item=77530], I suggest unequipping the trinket for this fight, as the Dragoling will kill the spores.