Double Damage!

[Froogle]

With my mage, I get 3.2k frostbolt crits, with my trinket and Arcane Power, I do 4.5k crits, meaning if I had this de"buff", I could do ~9000 critical strike frostbolts to this guy?

[Silentnite]

http://www.thottbot.com/q10176
That's the quest, with the name of the mob, with notes about the debuff. That should satisfy most of the questions. The only thing about all this is that the tower gives you a -50%damage debuff. Leave the tower and it goes away, go inside the towe and it comes back. The "double damage" comes from the fact that the mob doesn't come out of the tower if you can range him and not have him leash, hence you can stay outside of the debuff area. You don't recieve a buff to do double damage, the mob is just a weak mob.