These large tangled masses of tentacles are basket stars, some of the more complex looking brittlestars. Reaching up to about a meter in diameter, they hide away in dark holes in the reef by day and emerge at night to stand facing into the current on rocky or coral outcrops with their branching, many tendriled arms forming the shape of a radar dish to capture passing plankton. At the base of the arms is a ball of curling, branching tentacles. They are very light sensitive; even pointing a flashlight at them causes them to start folding up and running for cover. The ID is from Humann & DeLoach (2010) and Ryanskiy (2020) but is apparently considered somewhat tentative.
Created 6 April 2025