Your worst group?

[MongoJerry]

After that fight, clearing out the rest of the casters was easy, then all that was left was the boss.  Since no one else was left in the room, I charged him, and the rogue butchered on him, I kept shield-bashing him, and got a nice execute crit for the finish....then the turtles and crabs ate us!!!!!!  We just laughed and walked out of the instance after that, having completed all the quests.

... You know that the main boss mob in the instance is past the turtles and crabs, right? You light the four braziers one at a time. (Don't do more than one at a time. That's a bad scene -- seen it!). After each brazier, a group of mobs comes out -- crabs, turtles, whatever. After all four are lit and the mobs are killed, a door opens, and you get to see the big hydra mob at the end. No, there's no quest involving it, but fighting it is the big grande finale of the instance.