Blind Obedience - 6 R GTC

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.
"By the time your knees have worn through your robe, you may have begun to learn your place."
rare
Enchantment
From the Magic: The Gathering set Gatecrash.