Brightshore

This helmet was salvaged from the hollow head of the leonine steel predator that once guarded the Tomb of Oefelion.

As an action, you can emit a roar in a 60-foot cone. Each creature in that area must make a DC 19 Constitution saving throw. On a failed save, a creature takes 5d10 thunder damage, drops everything it's holding and is stunned for 1 minute. The stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. On a successful save, a creature takes half as much damage.

You cannot use the helmet's roar again until the next dawn.