The Glaucus atlanticus is a planktonic animal that belongs to the oceanic group known as Nudibranches. This is a sea slug that floats atop the sea, feeding on jellyfish.
"These small sea slugs float on the sea and are blown onto shore during the summer months onto Central Coast beaches. These were collected at MacMasters Beach in New South Wales. The Blue Sea Slug feeds almost exclusively on the tentacles of the stinging bluebottles. The larger ones are Glaucus atlanticus, with a single row of pinnae, while the smaller one has multiple rows of pinnae, hence is Glaucus marginatus."
Posted by YouTube user dougbeckers