That is a sea slug with a perfect coloring for hiding while it is floating on the sea surface. The sapphire side of the body is upward and blends with the blue water, while the silver part faces downward and could not be seen by predators from below. The blue dragon is not poisonous but it can gather poison from what it eats, and store it until it needs it.
The Dimplify team loves nature and we believe that the world we live in and the unique creatures around us are astounding. Have a look at the collection of 50 species we made that most of us have never even heard of. Scroll to the end of the article for the bonus photo which may be the coolest part!