Deep Sea Shop Theme (Puffy's Shipwreck), Destined for the Horizons 

In the deep sea you'll find what looks like an abandoned shipwreck. After entering it, you realize a shopkeeper named puffy is selling his wares. Puffy sells all kinds of bits and bobs he found in the ocean along with some food and weapons. Its much more convenient than traversing all the way back up from the deep.