Hidden Lake

The Hidden Lake is a subterranean lake in Snowy Penguin. It opens out to the sea, and a variety of sunken treasure drifts here from underwater. Waterfalls flow here into the sea from underground reservoirs. An underwater door here leads to the Underwater, but the door can only be opened with the Moss Key Pin. This room leads to the Cave Mine and the Forest.

Trivia

 * A broken Aqua Grabber sub is seen in the bottom-hand left corner.
 * The key to the Underwater area, mainly called the Moss Key Pin, can be obtained by following the silhouette of the giant squid in Puffle Rescue to a reef with a secret entrance to the area itself.