Ctenophora - "Also known as “comb jellies,” ctenophora emit a blue or green light that can only be seen in the dark. They also secrete ink that luminesces most brightly in the smaller bodies of young comb jellies. A rainbow effect is created when light scatters through the distinctive comb-like tentacles of the ctenophore."
Porpita porpita, commonly known as the blue button, is a marine organism consisting of a colony of hydroids found in tropical waters from California to the tropical Pacific, the Atlantic and Indian oceans It is often mistaken for a jellyfish, but although jellyfish and the blue buttons are part of the same phylum (Cnidaria), the blue button is part of the class Hydrozoa.
Cephea is a genus of true jellyfish in the family Cepheidae. They are found in the Indo-Pacific and East Atlantic. They are sometimes called crown jellyfish, but this can cause confusion with the closely related genus Netrostoma or the distantly related species in the order Coronatae.