Tendrils of Despair

Oracle Text

As an additional cost to cast this spell, sacrifice a creature.

Target opponent discards two cards.

Card Rulings

10/4/2004 If the player has fewer than 2 cards, they discard whatever they have.
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.