Depends on whether you mean the mob specifically or the encounter.
Kelekdrix in Inktu'Ta (GoD) springs to mind as one of those encounters that always seems to be on the verge of a wipe and is a 50/50 bet at best. Its just a tough encounter. (Compared to say Noqfiel, the boss of the zone, which is real fun encounter).
Its similar with Pyrique Redwing. Cipheron is nothing more than a speed bump on our way to RSS, but mention the idea of having another go at Redwing and half the raid team suddenly goes LD
.
The mob I simply hate the most - Cragbeast Queen. She is an absolute ***** to kill. (I'd rather spend a week fighting Rikkukin than to have to ever go back and fight CBQ again).
Edited, Wed Mar 8 23:11:33 2006 by Iluien