Sinister Monolith is a uncommon Artifact card from Bloomburrow (BLB), collector number 113. Current market price: $0.27 (foil $0.32), TCGplayer market prices via Scryfall.
At the beginning of combat on your turn, each opponent loses 1 life and you gain 1 life. {T}, Pay 2 life, Sacrifice this artifact: Draw two cards. Activate only as a sorcery.