I wasn’t even certain I had found another nudibranch when I came upon this individual.  Ceratosoma sp. #2 are especially tiny, reaching 8 mm (1/3″) when mature.  It wasn’t until I looked closely at the camera image that I realized this little nudibranch was quite beautiful, with a stand out tail, a yellow margin on its foot, a distinct lilac colour and a white margin on its whitish/lilac yellow-marked mantle.  Yet, at first it appeared to be nothing more than a spec of white on an algae, sand and sponge-covered rock. If it hadn’t moved slightly I would have thought it was just another ubiquitous piece of broken coral or shell.  See Sea Slugs of Hawaii site for more images.  Found in 10 ft (3 meters) of water in North Kihei, Maui, 2019.