Voltaic Conduit

Jagged lightning arcs from your fingertips in a direction you choose in a 60 foot line that is 5 feet wide. Each creature in the area takes 4d6 lightning damage and becomes rattled. If the lightning is blocked by an object at least as large as the line’s width, it ends there unless it deals enough damage to break through. When it does, it continues to the end of its area. On a successful Dexterity saving throw, a creature takes half damage and isn’t rattled.

The damage increases by 1d6 each time your power rating increases beyond III.