Uncharted Island

Uncharted Island is an island found in Phantom Hourglass, and is located in the northwestern quadrant.

Features
The island is located close to the Isle of Gust and is an island without a map. Therefore, it is simply referred to as Uncharted Island. However, once charted, the island resembles a spouting whale. This may be a reference to Oshus, whose true form resembles a white whale.

There's a cave on the island that can only be accessed if Link first solves a small riddle: "It steers with rudder, then makes spray! And third, it paddles, then sees a way!". Taking the shape of the island into account (that of a whale), Link has to hit four Gossip Stones in the order the riddle indicates. After that, Link can enter the cave in which dwells Cylos, the leader of the Golden Frogs. He reveals that he is friends with Oshus and gives Link the Cyclone Slate to help Link save him.