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.)

Bonus Round

Until end of turn, whenever a player casts an instant or sorcery spell, that player copies it and may choose new targets for the copy.

Cloven Casting

Whenever you cast a multicolored instant or sorcery spell, you may pay {1}. If you do, copy that spell. You may choose new targets for the copy.