Stratus Dancer is a rare Creature — Djinn Monk card from Dragons of Tarkir Promos (PDTK), collector number 80s. Current market price: — (foil $1.26), TCGplayer market prices via Scryfall.
Flying Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.) When this creature is turned face up, counter target instant or sorcery spell.