Give us the Zaratan sea turtle.
It's a giant sea turtle with an ecosystem on its back. Because it lives practically forever and almost never fully submerges and sleeps most of the time, the "island" on its back is covered with tropical plants, animals, people, and sometimes even unaware monsters. Rather than beaing something to fight (though you can try if you'd like), it is a creature perfect for a small adventure. Imagine the shock of the PCs when they discover that they're trapped on a giant sea turtle swimming through the ocean. The zaratan's armor makes it almost impenetrable, especially since the top of its shell is covered with earth and plants and rocks or even a tiny little mountain. It lives on a diet of giant squids, sacrifices from islanders, seaweed clusters, and basically anything else that strays into its water vacuuming turtle beak. PLEAS ADD ZARATAN TO BESTIARY 6. My sister and I have bean looking forward to one since the very start since it was one of my favorite creatures in Advanced D&D 2nd edition. Pathfinder is now the only tabletop RPG I play and I wish for the very best of Bestiary content. You never fail to deliver and I am always impressed by your published works.
http://vignette2.wikia.nocookie.net/cryptidz/images/8/8e/Zaratan---.jpg/rev ision/latest?cb=20140107015222