As an additional cost to cast Diabolic Intent, sacrifice a creature.
Search your library for a card and put that card into your hand. Then shuffle your library.
Collector Number: 22
2004-10-04 You must choose a card if there are any in your library.
2013-04-15 You must sacrifice exactly one creature to cast this spell; you cannot cast it without sacrificing a creature, and you cannot sacrifice additional creatures.
2013-04-15 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.
Gallery of all printings
Masterpiece Series: Amonkhet Invocations