Relentless Spirit

Flying
Relentless Spirit enters the battlefield
with X 1+/1+ counters
where X is the amount of mana spent to cast it,
or the amount of mana spent on the revive cost.
Revive {x}{u} (You may play this card from your graveyard for it's Revive cost with a revive counter on it.
if it would leave the battlefield with a revive counter, exile it instead.)