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.)
It's what comes after that, but they'll do the trick.
Pyreheart Walf {1RR} |Creature - Wolf Hound| 1/1 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.)