Arc-wave

A wave of thunder and lightning sweeps out from you. Each creature in a 5-foot by 30-foot line originating from you must make a Dexterity saving throw. On a failed save, a creature takes 1d8 thunder damage, 1d8 lightning damage, and their speed is reduced by 15 feet until the start of your next turn. On a successful save, the creature takes half as much damage and their speed isn't reduced.

In addition, the spell emits bright light for 20 feet, dim light for additional 20 feet, and a thunderous boom audible out to 300 feet.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for each damage type for each slot level above 2nd.