Shingle or helmet sea urchin. Seen in Hawaii, clinging to a rocky area during low tide. I had never seen this kind of sea urchin before. Evidently, the armored plates protect from waves.
Hey, any fans of #marineBiology here who can tell me what this creature is? If I had to guess, I'd say it was some kind of prawn development stage, but it seemed halfway to being a jellyfish, so I'm not sure. Spotted in Sooke, BC.