Geralf, Visionary Stitcher is a rare Legendary Creature — Human Wizard card from Innistrad: Double Feature (DBL), collector number 328. Current market price: $6.93 (foil $20.56), TCGplayer market prices via Scryfall.
Zombies you control have flying. {U}, {T}, Sacrifice another nontoken creature: Create an X/X blue Zombie creature token, where X is the sacrificed creature's toughness.