Nighstrid, Battle Enchantress

Flying
Whenever you cast a noncreature spell you may discard a card, if you do, draw a card. Whenever
you discard an enchantment card you may pay a
number of {r} mana equal to the amount of
colored mana in the enchantment spells mana
cost. If you do pay, exile it under Nighstrid,
Battle Enchantress and it gains all abilities of the
exiled enchantment.