Shellstar

With the rise of the predestar, a population of barnaclestars split off and found a solution. The shellstar has developed a calcium carbonate shell, which it uses to protect its soft body, and simple eyes, which it uses to detect predators so it can retract into the safety of its shell—though it does not always detect them in time and is still eaten sometimes. The shell is attached via modified baits, the same ones used to attach to crystal flora in the ancestor; as a result, it now lives on the seafloor, away from competition with its ancestor. It has also developed sexual reproduction via spore-like gametes, which it periodically releases into the water; it can still reproduce by fragmentation, but doing so is much harder due to its added complexity. It is otherwise very similar to its ancestor; it spends its days sitting around, filtering small cells and bits of dead organisms out of the water with its bristly arms.