Invasion of Karsus // Refraction Elemental

Invasion of Karsus: (As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.) When this Siege enters, it deals 3 damage to each creature and each planeswalker. Refraction Elemental: Ward—Pay 2 life. Whenever you cast a spell, this creature deals 2 damage to each opponent.