Lair of the Ashen Idol is a common Plane — Azgol card from Planechase Anthology Planes (OPCA), collector number 46. Current market price: $2.75, TCGplayer market prices via Scryfall.
At the beginning of your upkeep, sacrifice a creature. If you can't, planeswalk. Whenever chaos ensues, any number of target players each create a 2/2 black Zombie creature token.