As an additional cost to cast Mind Extraction, sacrifice a creature.
Target player reveals his or her hand and discards all cards of each of the sacrificed creature's colors.
10/4/2004 If you sacrifice a colorless creature, you get to see their hand but they discard no cards.
10/4/2004 If you sacrifice a multicolored creature, all cards that share at least one color with the creature are discarded.
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.