It's the new unique that came with patch 1.11. You get it through a very lengthy process of killing (uber) bosses and transmuting.
It's a Unique Large Charm that gives:
+ 3 to a random class skill
+ Points into stats (not sure of the range)
+ Points into resists (not sure of the range)
+ Chance to cast Diablo's Firestorm on striking (not sure of ctc%)
+ Charges on some skill I'm not sure of
