Lair of the Ashen Idol is a common Plane — Azgol card from Planechase 2012 Planes (OPC2), collector number 24. Current market price: $4.36, 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.