Bitter Bone, Grafted Lord

Menace
Other skeletons you control get +0/+1
Whenever a skeleton creature would be regenerated or the ability of a skeleton creature in your graveyard would be activated, you may exile it with a graft counter on it. Bitter Bone has +X /+X, where X is the half the total power and toughness of all creatures in exile with graft counters on them rounded up.
When Bitter Bone leaves the battlefield, return all creatures with graft counters on them to the battlefield tapped . You lose life equal to the numbe