Amplexidiscus coral fluorescing at night. Commonly known as the mushroom anemone, this coral is partially retracted here. It has been photographed under blue light at night, resulting in the fluorescence seen here. Amplexidiscus is an example of a corallimorpharian, an intermediate life form between sea anemones and hard corals. Photographed in Lembeh Strait, off Sulawesi, Indonesia.