You see Bonelord's Phylactery.
Notes
Part of The Roost of the Graveborn Quest, during the fight against the Bone Overlord. Since the Bone Overlord is not an actual creature, the Phylactery is what actually drops the loot from the boss.
Abilities
Damage Taken From Elements
Physical 
Death 
Holy 
Ice 
Fire
Energy
Earth
Drown
Location