The Sea is a dungeon that is accessible after completing the cave entrance. To get to The Sea, just enter The Pier and then click on the Jump into the sea button.
Because the sea is an infinite level, if you leave it or die, you will always keep the candies and the treasures you found. The treasures you can find include the Shell Powder, Magical sponge, Magical green shark fin, Magical red shark fin and the Magical purple shark fin.
There are many enemies in The Sea. There are big fish at first, and then some small fish. After a while, jellyfish will start to appear. Then, sharks and sea snakes will swim by. There can be a mix of these animals as you go along.