Any updates on this? One guy i was raiding with claimed he knew for a fact that you could use the thing from Asation on the stairs in the tunnel before the third boss in 16 man HC.
I heard the same thing, it's somewhere between a rumor and datamining right now. Apparently, a secret bonus boss is supposed to appear there if you throw the orb on a mob with <20% life.
Here are two debuff tooltips that were supposedly gathered from the game files:
Something is taking advantage of this creature’s weakened state and feeding off its essence…
A powerful entity is gathering and attempting to manifest itself, searching for a point of focus…
My guild tried to do it but it did not work. The main problem is that you cannot use the orb while in combat, and it has a very small range. As soon as you approach an enemy with it, he will spot you. Also, in HM the elite mobs cannot be mezzed by stealthers but are immune to CC.
I am assuming that the bonus boss is currently not fully added in-game, and that they will add a red message like in the Asation cave when it is possible to do it, so that players will know this is the right spot.