Jadar, Ghoulcaller of Nephalia is a rare Legendary Creature — Human Wizard card from Innistrad: Midnight Hunt Promos (PMID), collector number 108p. Current market price: $1.67 (foil $3.30), TCGplayer market prices via Scryfall.
At the beginning of your end step, if you control no creatures with decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)