Sacrifice | Magic: The Gathering
Formats Sacrifice is Legal in
Official Oracle Text for Sacrifice
Add to your mana pool an amount of equal to the sacrificed creature's converted mana cost.
Official Rulings for Sacrifice
4/15/2013 : You must sacrifice exactly one creature to cast this spell; you cannot cast it without sacrificing a creature, and you cannot sacrifice additional creatures.
4/15/2013 : Players can only respond once this spell has been cast and all its costs have been paid. No one can try to destroy the creature you sacrificed to prevent you from casting this spell.