Tulliver's Repetitive Percussion

You cause a burst of concussive sound to explode outwards from a point you choose within range. Make a ranged spell attack against the target. On a hit, the target takes 4d6 thunder damage immediately and 4d6 thunder damage at the end of its next turn. They must also make a Constitution saving throw each time they are affected. On a failure, they are knocked prone and deafened for 10 minutes. On a miss, they take the initial 4d6 thunder damage, but not the second round's damage, and they do not need to make a saving throw for the extra effect.

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