Smokestack is a rare Artifact card from Mystery Booster 2 (MB2), collector number 232. Current market price: $1.09 (foil $10.55), 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.