Chain lightning
Does lightning damage. Strikes target stack or war machine, then arcs to strike the next-closest target, repeating until the chain reaches its target limit or until no valid targets remain. Damage to each target is half the damage to the previous target, being 100% then 50% after this 25% then 12.5% and so on. Will only strike a target once. If the spell is resisted after it has already struck at least one target, it will continue arcing to the next target.