Wandering Spirit

Wayfarer {3}{u} ({3}{u}: Exile this creature. Activate this ability only as a sorcery. At the beginning of your next upkeep, return it to the battlefield. It gains haste until end of turn.)
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.)
Some spirits never learn of their demise.