Thundercrack

You evoke a resounding wave of thunderous force to erupt nearby. Each creature within 15-foot radius within range must make a Constitution saving throw. On a failed saving save, a creature takes 4d8 Lightning damage and 4d8 Thunder Damage, and becomes knocked prone and is  deafened for 1 minute. On a successful save, the creature takes half as much damage and suffers no other effects. At the end of a creatures turn it can retry the saving throw to get rid of the deafened condition.

If the creature is Huge or larger size, it has advantage on its saving throw. A creature made of inorganic material such as stone, crystal, or metal has disadvantage on this saving throw. If a creature is both, these effects cancel out.

In addition, unsecured objects that are completely within the area of effect are automatically thrown to the ground and likely break due to the spell's effects, and the spell emits a thunderous boom audible out to 600 feet.

 At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the both damage types increase by 1d8 for each slot level above 5th.