Shalltear's Bloodcalling

Whenever a creature, player or planeswalker is
dealt combat damage put a Blood counter on
Shalltear's Bloodcalling. Whenever a creature an opponent controls dies you may pay X Blood counters, if you do Scry X and gain X life, where
X equals that creature's toughness.
At the end of any of your turns if there are no
Blood counters on Shalltear's Bloodcalling exile it
and create a 3/2 Black Blood Weird creature
token with Lifelink and Infect.