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From Pathfinder Gamemastery Guide, which isn't enabled.

Shrieker

HAZARD -1
Stealth +2
Description This human-sized purple mushroom emits a piercing shriek when disturbed.

Disable DC 18 Survival to carefully approach and cut the mushroom's air sac without triggering the shrieker

AC 12; Fort +8, Ref +2
HP 9 (BT 4); Immunities critical hits, precision

Shriek
Trigger A creature or light source approaches within 10 feet of the shrieker or the shrieker takes damage.

Effect The shrieker emits a deafening screech that deals 1d6 sonic damage to creatures within 30 feet (DC 16 basic Fortitude save; creatures that critically fail this saving throw are Deafened for 1 minute).
Reset 1 minute
Pathfinder Gamemastery GuideOGL