From PathfinderWiki

Vhunsaub is thought to be an ancient underwater treasury of the Ghol-Gan, and is located among the Cannibal Isles of the Shackles. Many have tried to explore the ruin, but none have progressed past the entrance guarded by a magically compelled sea serpent.1


  1. Mike Shel. “Shackles Gazetteer” in Isles of the Shackles, 17. Paizo Inc., 2012