Death Baron is a rare Creature — Zombie Wizard card from Core Set 2019 Promos (PM19), collector number 90p. Current market price: $5.99 (foil $9.02), TCGplayer market prices via Scryfall.
Skeletons you control and other Zombies you control get +1/+1 and have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)