Wrath of the All-Father

You raise your arm aloft and bring down a bolt of lightning that strikes a target of your choice that you can see within range. Bolts then leap from that target to any targets of your choice, each of which must be within 5 feet of the first target. A target can be a creature or an object and can be targeted by only one of the bolts

All targets must make a Dexterity saving throw. The original target takes 5d8 lightning damage on a failed save, or half as much damage on a successful one. The secondary targets take 3d6 lightning damage on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for the original bolt and 1d6 for the secondary bolts for every spell level above 4th.