Nyctirax, Deathless Scavenger

Flying, hexproof from white and from green
You may cast Nyctirax, Deathless Scavenger from your graveyard.
Whenever Nyctirax, Deathless Scavenger attacks, return target creature card with converted mana cost less than Nyctirax, Deathless Scavenger's power from your graveyard to the battlefield tapped and attacking. Sacrifice it at the beginning of the next end step.