Smokestack is a mythic Artifact card from From the Vault: Annihilation (V14), collector number 11. Current market price: — (foil $5.64), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you may put a soot counter on this artifact. At the beginning of each player's upkeep, that player sacrifices a permanent of their choice for each soot counter on this artifact.