Durgan Bloodtracker

When Durgan Bloodtracker attacks, for each
blood token defending player controls, it gets
+1/0 until end of turn.
Whenever a creature dies, that creature's
controller creates a blood token. (It's an artifact
with "{1}, {t}, Discard a card, Sacrifice this artifact:
Draw a card.")
Whenever a player sacrifices a blood token,
Durgan Bloodtracker deals damage to that player
equal to its power.