Sea Clouds, also called Ocean Clouds, are large water-like clouds. They form seas in the sky. One can almost sail on it as if it were water except that Sea Clouds are slightly less dense than water, and as such, things that are drop into it will sink faster than in normal water. Another difference of seas made of Sea Clouds from seas made of water is that there is no sea floor. However, they still affect Devil Fruit users like a regular body of water would. These clouds form two known seas: the White Sea and the White White Sea.