Zyym, Mesmeric Lord is a rare Legendary Creature — Vampire Wizard card from Mystery Booster Playtest Cards 2021 (CMB2), collector number 104. Current market price: $0.35, TCGplayer market prices via Scryfall.
Flying, deathtouch When Zyym, Mesmeric Lord enters the battlefield, target opponent chooses an order for the cards in their hand, then reveals them one by one until you say stop. That player then discards the most recently revealed card.