Will of the Naga

Text:

Delve (Each card you exile from your graveyard while casting this spell pays for .)
Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Rulings:

• 11/24/2014 Will of the Naga can target creatures that are already tapped. Those creatures won’t untap during their controller’s next untap step.
• 11/24/2014 Will of the Naga tracks the creatures, but not their controllers. If any of those creatures changes controllers before its first controller’s next untap step, then it won’t untap during its new controller’s next untap step.
• 11/24/2014 If you chose two targets and one is an illegal target as Will of the Naga resolves, that creature won’t become tapped and it won’t be stopped from untapping during its controller’s next untap step. It won’t be affected by Will of the Naga in any way.
• 11/24/2014 You exile cards from your graveyard at the same time you pay the spell’s cost. Exiling a card this way is simply another way to pay that cost.
• 11/24/2014 Delve doesn’t change a spell’s mana cost or converted mana cost. For example, the converted mana cost of Tasigur’s Cruelty (with mana cost <img src="/Handlers/Image.ashx?size=small&amp;name=5&amp;type=symbol" alt="5" align="absbottom" /><img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" />) is 6 even if you exile three cards to cast it.
• 11/24/2014 You can’t exile cards to pay for the colored mana requirements of a spell with delve.
• 11/24/2014 You can’t exile more cards than the generic mana requirement of a spell with delve. For example, you can’t exile more than five cards from your graveyard to cast Tasigur’s Cruelty.
• 11/24/2014 Because delve isn’t an alternative cost, it can be used in conjunction with alternative costs.