Rakdos Gravepurger

Unearth {b}{r}
Unleash (You may have this creature enter the
battlefield with a +1/+1 counter on it. This
creature cannot block as long as it has a +1/+1
counter on it.)
Undying (When this creature dies, if it had no
+1/+1 counters on it, return it to the
battlefield under its owners control with a +1/+1
counter on it.)