Lose Your Illusion (25 player)

Kill Thorim on hard mode.

Before Thorim can be faught, part of the raid must run a gauntlet to reach him. After 3 minutes Sif despawns. After 5 minutes the raid is wiped. Normal mode requires engaging Thorim between 3 and 5 minutes after the encounter is started. Engaging Thorim in less then 3 minutes forces the raid to fight both Sif and Thorim simultaneously and counts as the hard mode of the encounter.

If at this point you wipe, you will still be granted the Heroic: Siffed achievement. If you manage to kill Thorim, you will also recieve the Heroic: Lose Your Illusion achievement.

Sif cannot be killed, but does attack the raid with Frostbolt Volley, Frost Nova and Blizzard. She also removes the Touch of Dominion debuff from Thorim, increasing his damage by 67% and his health by 43%.

[edit]Touch of Dominion used to reduce damage by 20%, but now reduces damage by 40%. So not having that buff increases Thorim's damage by 67% instead of 33%. Assuming his unmodified damage output stayed the same, this should not be seen as a buff to the hard mode, but rather as a nerf to normal mode.[/edit]

Achievement referred to http://en.wikipedia.org/wiki/Use_Your_Illusion_I and http://en.wikipedia.org/wiki/Use_Your_Illusion_II .
Now I want the "Appetite for Destruction" (http://en.wikipedia.org/wiki/Appetite_for_Destruction) achievement :-)

I prefer to think of it as a reference to Use Your Allusion, from Tony Wonder.