Riverwheel Aerialists is a uncommon Creature — Djinn Monk card from Khans of Tarkir (KTK), collector number 51. Current market price: $0.12 (foil $0.40), TCGplayer market prices via Scryfall.
Flying Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)