The Trinity Barnacle has a round, brownish-yellow shell with a recess in the center. The recess is colored dark green and has three luminescent circles in the middle.
Trinity barnacles can be found near sea vents and geothermal hotspots, often in clusters. They feature a thick capitulum (shell casing) that allow them to survive in very warm water temperatures. Mature barnacles develop a triad of ocelli, which are rudimentary photoreceptors.