Warchief Mozenrath
Ok, more than one picture. This guy is the giant dragon that roams Azshara. For those of you who don't know, this guy is unique in the sense that most bosses are fought in special thigns called "instances" where only your party (5,10,15, or 40 people max depending on which one) can go in, and nobody else. But this guy roams around out in the open, which resuted in a huge fight (Over 200 alliance and horde) over who gets to kill him. Killing alliance n00bs is even more fun that going after the boss himself.
In the end the horde killed him and he dropped 6 realy good items. Due to a certain bug, one guy stole all six items for himself.
Oh yeah, I forgot to mention he took over half an hour to kill. Over 30 minutes!