Thunder Howl

You howl out a thunderous wave of energy. Each creature within 20ft of you (Not including yourself) must succeed on a Constitution saving throw or take 6d6 Thunder damage and be pushed away 10ft away from you. A creature that succeeds on its saving throw takes half as much damage and is not pushed back.

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 4.