Lilah, Undefeated Slickshot

Prowess (Whenever you cast a noncreature spell,
this creature gets +1/+1 until end of turn.)

Whenever you cast a multicolored instant or
sorcery spell from your hand, exile that spell
instead of putting it into your graveyard as it
resolves. If you do, it becomes plotted. (You
may cast it as a sorcery on a later turn without
paying its mana cost.)