Thundaga

A spark of electricity launches from your pointing finger to a point you choose within range and then detonates with a loud pop into a cloud of lightning arcs lasting a few seconds. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 lightning damage on a failed save, or half as much damage on a successful one.

The lightning spreads around corners.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.