Deep-Fiend Lurker

Reveal Deep-Fiend Lurker from your hand: Exile target Instant or Sorcery spell you control and cast Deep-Fiend Lurker reduced by the exile spell's converted mana cost.
Instant and Sorcery spells you cast have "As an additional cost to cast this card you may pay {u}. If you do, tap target nonland permanent an opponent controls. That permanent doesn't untap during it's controllers next untap step.