True dragons roar

 You let out a roar fierce enough to rival that of a true dragon and frightening enough to send those unlucky to be on the receiving end of this into utter madness.  All enemies within 60ft of you must make a charisma saving throw on a failed save the targets take 12d10 thunder damage and gain a short term madness (roll on page 158 of DMG) or half as much damage on a successful save and not receive a madness.