pretty sure, kerafyrm has a 30 second tank DT and a 30 second AOE DT for the platform. the only time it has ever been KILLED without the use of third party Z-targeting hacks, was on Rallos Zek. It was attempted twice in two days, i was online when it was going on lol.
Kerafyrm the Sleeper was taken on by 300 people from different guilds, the way they took to the task was simple, ring the upper balcony with ranks of raidforce personnel, Treat the sleeper like a reverse wave spawn quest. He just AoEd everyone? good, next wave, dead get pulled, rezzed, set back at the end of the wave line.
For interesting trivia, the first day they tried the sleeper on RZ, it was despawned by the GM's at 26% after 3 hours of player effort, because the mob was supposed to be unkillable due to the story line. If the sleeper doesnt awaken and kill everyone and disappear, how the heck are we gonna have any more expansions??? right??? and by THAT time we already HAD expansions, so the storyline was invalidated by the sleepers death.
Anyhow, the next day, they reset the encounter, and the players were allowed to kill him. No loot. no flags, no nothing. just bragging rights as to being on the force that destroyed the gameline on Rallos Zek... and who said PvP servers were hard to play on...