It is a quest you get in Zul'drak similar to the Ring of Blood in Nagrand. You will need at least 1 x 85 tank, 2 x 80's or a group of 5 x 75's to complete it. You face i believe 5 bosses one at a time each getting progressively harder. I know one is is worm, mammoth, rhino from my main accomplishing the quest. At the end you are rewarded with a Blue weapon dependant upon your class that is good enough quality to last you until you hit level 80.