Thunderburst

You summon a bolt of lightning that strikes you and creates a thunderous boom. Each creature in a 15-foot cube originating from you must make a Constitution saving throw. On a failed save creatures take 2d6 thunder damage and are blinded and deafened until the end of their next turn. On a successful save creatures take half as much damage and are not blinded or deafened.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1st.