Twin Bolt
From Tarkir: Dragonstorm set


Twin Bolt
Instant
Twin Bolt deals 2 damage divided as you choose among one or two targets.
Rulings
- You choose whether Twin Bolt has one target that will be dealt 2 damage or two targets that will each be dealt 1 damage as you cast Twin Bolt.
- If you cast Twin Bolt with two targets and one of those targets becomes illegal before Twin Bolt resolves, the remaining legal target will be dealt 1 damage. You can’t change the original division of damage.