text: If Aerie Ouphes has no -1/-1 counters on it when you sacrifice it to activate its first ability, persist will return Aerie Ouphes to the battlefield with a -1/-1 counter on it before that ability resolves. The ability will check the power of Aerie Ouphes at the time you sacrificed it, not the power of the returned Aerie Ouphes (which is actually a new object with no relation to its previous existence).