A colorful Peacock spider, Maratus speciosus. Photo: Jurgen Otto.
Harvard University wrote:
Peacock spiders, known for their elaborate mating dances, use incredibly dark, “super black” patches on their body to enhance nearby colors. This makes colors look impossibly bright, or even glowing, an optical illusion also used by birds-of-paradise.The spider evolved microlenses on its body surface, which manipulate light in the same way human-made materials do.