Seraphic Steed is a rare Creature — Unicorn Mount card from Outlaws of Thunder Junction (OTJ), collector number 364. Current market price: $0.37 (foil $0.45), TCGplayer market prices via Scryfall.
First strike, lifelink Whenever this creature attacks while saddled, create a 3/3 white Angel creature token with flying. Saddle 4 (Tap any number of other creatures you control with total power 4 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)