Erden's Ultimate Lightning Bolt

Thunder booms and storm clouds roll in as a strike of lightning forming a line 200 feet long and 15 foot wide blasts out from you in a direction you choose. Each creature in the line must make a Dexterity saving throw DC 20. A creature takes 10d10 lightning damage on a failed save, or half as much damage on a successful one.

The lightning ignites flammable objects in the area that aren't being worn or carried. Any creatures that are caught in the blast are stunned and deafened for 1 round.