Not Half Bat Potion

Sacrifice a Bat, sacrifice and enchantment,
put a +1/+1 counter on a creature an opponent controls, {t}: Create a 3/3 white and black
Spirit Bat with flying, lifelink and extort (Whenever you cast a spell, you may pay {w}
or {b}. If you do, each opponent loses 1 life
and you gain that much life.)