Aetherstorm Roc is a rare Creature — Bird card from Kaladesh Promos (PKLD), collector number 3s. Current market price: — (foil $1.00), TCGplayer market prices via Scryfall.
Flying Whenever this creature or another creature you control enters, you get {E} (an energy counter). Whenever this creature attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.