Shriek. Trigger: A creature or a source of Bright Light moves within 30 feet of the shrieker. Response: The shrieker emits a shriek audible within 300 feet of itself for 1 minute or until the shrieker dies.
If exposed to light or otherwise disturbed, mushroom-like shriekers emit a high-pitched noise that gives them their name. This wailing might alert other creatures or attract predators.