Portentous Plagiarist

Flying

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Whenever Portentous Plagiarist attacks, defending player reveals their hand. You may copy an instant or sorcery card in it with mana value less than or equal to Portentous Plagiarist's power. If you do, you may cast the copy without paying its mana cost.