They wouldn't put a NiM tier boss in a SM op.
At least give us a screenshot.
Plus I can't see them making us spawn a boss in a boss fight. They couldn't even get the fight to work properly when it was released, that sounds like bug hell.
There were files mined a while back on what the boss might be, but I can't post them here.
Yeah, I remember the 100% burn phase lol...
He did say he found it on the past throne during phases 2 and 3... I'm wondering if it will be designed so that it has to be summoned during the small window of time that is usually taken up with the tank bringing the little datacron to the throne or something... (remember that past has no boss in that room in phase 3) Pure speculation at this point, obviously, but still something to keep my mind busy while we wait for Nightmare DF. I'll keep an eye out for it during that phase tomorrow (we run 16 man HM two-three times a week) and see if I can get a lock on it and a screenshot, if it is in HM as well.