Ajani's Lightning Helix

A stroke of lightning forming a line 120 feet long and 5 feet wide blasts out from you in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 6d6 lightning damage  on a failed save, or half as much damage on a successful one. Any friendly creatures in the line heal  4d6 damage.

The lightning ignites flammable objects in the area that aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.

"Rage is not the answer. Rage followed by fitting vengeance is the answer." - Ajani