A photophore is a light-emitting organ which appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors. The light can be produced from compounds during the digestion of prey, from specialized mitochondrial cells in the organism, called photocytes ("light producing" cells), or, similarly, associated with symbiotic bacteria in the organism that is cultured.