Undead Alchemist is a rare Creature — Zombie card from Innistrad (ISD), collector number 84. Current market price: $0.90 (foil $4.23), TCGplayer market prices via Scryfall.
If a Zombie you control would deal combat damage to a player, instead that player mills that many cards. Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.