Brontide

You pull a whip of pure lightning from the aether. The whip coils and writhes in your hand, seemingly ready to slay all those who would challenge you.

As a bonus action after casting this spell you can crack the whip in from of you in a 15 foot cone. Each creature in the cone must make a Dexterity saving throw or suffer 6d8 lightning damage, or half as much on a save.