Midnight Clumpstar
The midnight clumpstar developed from clumpstars that crossed into Vailnoff Ocean and Flisch Sea and extended their range deep into the midnight zone. They also continued the growth trend, with polyps now reaching a height of about three centimeters.
Their most significant developments have been internal, as they needed to be able to handle the low oxygen of their new environment, while still oxygenating the tissue of their larger bodies. As a result, the midnight clumpstar now has a distinct circulatory system, with a tiny heart at the base of their bodies. Their blood uses hemocyanin, a blue pigment that is particularly efficient in a cold, low-oxygen environment. Above the heart, they have a distinct digestive pouch. They retain their ancestral nerve network, which has no ganglia. Their repertoire of behaviors is very simple, merely the ability to retract into their shell when threatened. As a further response to the low oxygen, their gills have grown considerably longer, extending far above. They feed on detritus falling from above as well as on cells in their environment.
Due to the low-light conditions, vision was no longer an efficient sense. Midnight clumpstar instead relies on sensing vibrations through their filter-feeding hairs and their gills. Their free-swimming larvae retain their ancestral eyes, but these are lost upon adulthood.
Midnight clumpstars release spore-like gametes throughout their life, which combine to form a new larva. These larvae swim freely until they grow enough to secrete a shell, at which point they sink to the seafloor. While it is possible for a larva to join an existing clump, this is rare. Instead, they usually settle onto their base, with the arms facing upward, and secrete an individual shell shaped like a ring around them. They will develop from a single individual into a clump asexually: One arm will split off and grow into a complete adult, which will secrete a new portion of the communal shell.