Mordenkainen's Lost Notebook
3-level Evocation
You cause an extremely loud thunderclap to erupt at a point you can see within range. Each creature in a 20-foot radius sphere centered on that point must make a Constitution saving throw. On a failed save, a target takes 3d8 thunder damage, is deafened, and knocked prone. On a successful save, the creature takes half as much damage and isn’t knocked prone. The creature can repeat the saving throw at the end of each of its turns to end the deafened condition. Creatures already under the effects of a painful echoes spell (q.v.) make this save with disadvantage, and on a failure are also stunned, along with the above conditions. In addition, the spell emits a thunderous boom audible out to 300 feet from its point of origin.