Blind Obedience is a rare Enchantment card from Gatecrash (GTC), collector number 6. Current market price: $5.08 (foil $7.66), TCGplayer market prices via Scryfall.
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.) Artifacts and creatures your opponents control enter tapped.