Bitterblossom is a mythic Kindred Enchantment — Faerie card from Wilds of Eldraine: Enchanting Tales (WOT), collector number 72. Current market price: $28.22 (foil $39.48), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you lose 1 life and create a 1/1 black Faerie Rogue creature token with flying.