Zaratan

Zaratan are behemoth-sized sea turtles - so large, in fact, that entire ecosystems can develop on their stony shells. They spend their millennia-long lives mostly in slumber, drifting on the surface of the ocean, mouths slightly open to capture any creatures that explore the 'cave', all of whom are reflexively swallowed. 
The largest zaratan in the known world is the island of Tortuga.
Category:Monstrosities