In Dragon Soul our Warrior tank got the first heroic gurthalak on the server - it used to randomly proc tentacles that would channel mind flays at whoever the warrior was targetting. The trick with warriors was, Sweeping Strikes hits and Bladestorm hits counted as single target damage hits as far as the proc rate was concerned - so SS+BS = chance at 0-5 tentacles spawning. I carried him in 3's up to 2100ish, but ya - whenever 3-5 tentacles spawned at once and all channeled the kill target to death: it was a beautiful sight to behold
In my mind I always used to pretend the tentacles were my doing, because they should clearly be a shadowpriest ability
(Of course, apparitions would work too!)