Arc Lightning
Sorcery
Arc Lightning deals 3 damage divided as you choose among one, two, or three targets.
Rainclouds don't last long in Shiv, but that doesn't stop the lightning.
Illustrated by
The List#USG-174CommonEnglishLegality
Rulings
Sep 20, 2014
You choose how many targets Arc Lightning has and how the damage is divided as you cast the spell. Each target must receive at least 1 damage.
Sep 20, 2014
If some of the creatures are illegal targets as Arc Lightning tries to resolve, the original division of damage still applies but no damage is dealt to the illegal targets. If all targets are illegal, Arc Lightning doesn’t resolve.