New Grasp Rune in PBE
https://2.bp.blogspot.com/-ol9T3bA9oo0/WihY0vo0oyI/AAAAAAAA06E/vEtn5aM9BRkXfRP1sPk4AbhSqA2WfvafwCLcBGAs/s1600/grasp.png
Is busted, and I love it.
Basically once you "proc" Grasp your bonus dmg stays effective as long as you are in combat, and if you proc it again you get a stack. If you stay in combat by hitting minions and procing grasp on champions you can build stacks up indefinitely.