This scene drew my attention because of the smooth, round rock nestled into a matching recess in the shore (bottom left in the top photo). It was when I zoomed in (bottom photo) that I noticed the large number of helmet urchins stuck to the shoreline. These cheerful-looking purple blobs live in the harsh tidal zone, and area of crashing waves and surging water. They feed on algae that grows there.
In the middle photo, an a’ama crab skirts a colony of urchins. When the tide comes in, the crab will move to higher ground, but the urchins will stay put, tenaciously defying everything the ocean throws at them.