Fervent Mastery is a rare Sorcery card from Strixhaven: School of Mages Promos (PSTX), collector number 101p. Current market price: $0.40 (foil $0.29), TCGplayer market prices via Scryfall.
You may pay {2}{R}{R} rather than pay this spell's mana cost. If the {2}{R}{R} cost was paid, an opponent discards any number of cards, then draws that many cards. Search your library for up to three cards, put them into your hand, shuffle, then discard three cards at random.