Grim, the Misanthrope

When Grim, the Misanthrope enters the battlefield, destroy target Human, Soldier or
Knight.
Put X +1/+1 counters on Grim, where X is the
power of the destroyed creature.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its
owner's control with a +1/+1 counter on it.)