Chorus of Thunder

You utter, shout, or sing a short verse to damage and deafen your enemies. A cacophonous clap of thunder slams out from you in a 30-foot cone that is audible out to 300 feet. Each creature in the cone must make a Constitution saving throw. On a failed save, a creature takes 4d6 thunder damage and is deafened until the end of the next turn. On a successful save a creature takes half the damage and isn't deafened.

When you cast this spell, up to four friendly creatures within 30 feet of you that you can see can use a reaction each to join the chorus with a clash of weapon against shield, a ringing shout, or other loud noise. For each creature that joins the chorus, the spell's damage increases by 1d6, and the cone's size increases by 5 feet.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the primary damage increases by 1d6 for each slot level above 3rd.