The snallygaster emits a loud squawk like a screeching whistle in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw. On a failure, a creature takes 49 (14d6) thunder damage and is stunned for 1 minute. On a success, a creature takes half the damage and isn't stunned. A stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.