Gibbering mouthers are revolting mounds of eyes and mouths that yammer on unceasingly, slowly driving anyone around them insane. Some think they are a lesser version of a shoggoth, while others believe that they were sent by the gods as punishment for some forgotten transgression. Never satiated, they roam caves, sewers, and other underground locations searching endlessly for food. They have an intelligence similar to a lesser human's and can speak Aklo, one of the languages of the Darklands.
These foul aberrations have been spotted in underground environments throughout the Inner Sea region, including beneath the antediluvian city of Kaer Maga in Varisia, the ruins of Nal-Kashel off the coast of Cheliax, and the Darklands realm of Sekamina and the Orvian Vaults. A berserk gibbering mouther named Galulab'daa is said to serve the god Rovagug in his prison deep below the surface of Golarion.
- Jason Bulmahn. (2009). Bestiary (First Edition), p. 153. Paizo Publishing, LLC. ISBN 978-1-60125-183-1
- James L. Sutter. (2010). City of Strangers, p. 59. Paizo Publishing, LLC. ISBN 978-1-60125-248-7
- Brandon Hodge. (2010). From Shore to Sea, p. 14. Paizo Publishing, LLC. ISBN 978-1-60125-257-9
- James Jacobs and Greg A. Vaughan. (2008). Into the Darklands, p. inside front cover. Paizo Publishing, LLC. ISBN 978-1-60125-140-4
- Sean K Reynolds. (2008). Gods and Magic, p. 32. Paizo Publishing, LLC. ISBN 978-1-60125-139-8
- Sean K Reynolds. (2009). Rovagug. The Impossible Eye, p. 67. Paizo Publishing, LLC. ISBN 978-1-60125-179-4