What is that? Is that some kind of animal from final fantasy?
It is a planktonic animal that belongs to the oceanic group known as
Nudibranches. Glaucus atlanticus, that's what we call it. However, Nudibraches is also thought of as an "unusual" group of molluscs. Glaucus atlanticus is a species of small-sized blue sea slug, a pelagic aeolid nudibranch, a marine gastropod mollusk in the family Glaucidae. It also has plenty of names, like sea swallow, blue glaucus, blue sea slug and blue ocean slug.