Shrieker 2014

The shrieker emits a concentrated burst of sound at one creature it can sense within 30 feet of it. The target must make a DC 10 DEX save, taking 2 (1d4) thunder damage on a failed save, or half as much damage on a successful one.

The shrieker emits a high-pitched shriek audible within 300 feet of it. Each creature within 30 feet of it that isn't a Plant and that can hear the shriek must succeed on a DC 10 WIS save or be frightened until the shriek ends. The shrieker must use a bonus action on its subsequent turns to continue shrieking. It can stop shrieking at any time. The shriek ends if the shrieker is incapacitated.<br>A frightened creature can repeat the save at the end of each of its turns, ending the effect on itself on a success. A creature that successfully saves is immune to the frightened effect of this shrieker's Shriek for the next 24 hours.

When bright light or a creature other than a Plant moves to within 30 feet of the shrieker, the shrieker can use Shriek, if it isn't already shrieking.