The legend of the Octosaurus Rex. Deep sea archeological digs have revealed absolutely nothing about this prehistoric creature, because they are just that elusive. We know about them only because the great pirate, Iron-Leg Jack, documented the tale of the last Octosaurus that followed his ship, the HMS Drunkin Duckling, through the high seas in the early 15th century. The Octosaurus Rex is a prehistoric eight-legged sea monster. Get him before he gets you!! Bendable height: 3 inches. Tentacle span: 7.5 inches.