long-spined sea urchin
... that the long-spined sea urchin reacts to a shadow falling on it by angling its spines towards the possible predator?
... that the <b id="mwAiM"><a href="./Diadema_savignyi" id="mwAiQ" rel="mw:WikiLink" title="Diadema savignyi">long-spined sea urchin</a></b> <i id="mwAiU">(pictured)</i> reacts to a shadow falling on it by angling its <a href="./Spine_(zoology)" id="mwAiY" rel="mw:WikiLink" title="Spine (zoology)">spines</a> towards the possible <a href="./Predation" id="mwAic" rel="mw:WikiLink" title="Predation">predator</a>?