Necromantic Dragon Bone Clicky
This item is one of the better DD clickies that you can get in the game and in comparison to the other Anniversary clicky, Bottled Essence of Vex, this is the far superior one. It only hits for 2k more damage but it also heals you, being a lifetap and all - and it's not a targeted AE ability which means it always hits its target.
Note: This item does not benefit from any spell AAs, spell focuses or spell damage stats
I personally get this item on every one of my casters since it makes a nice item to weave inbetween spell casts or to cast during fights where I am trying to conserve my mana as much as possible.