Geletaventrian Coproworm
The Geletaventrian Coproworm split from its ancestor and became a commensal of Geletaventrian species, feeding on their waste products. They became smaller and more flexible, thinning their exoskeletal plates somewhat and developing a greater number of segments. They have lost their photosynthetic capabilities and are now an unpigmented grey. They have also lost their spines, as without predators, it has no need of them. They spend their entire adulthood clinging near the anuses of Geletaventrians, feeding on their waste as it flows out. Their size varies wildly depending on their host's size, with some exceptional individuals growing to almost 10 centimeters long.
As self-fertilizing hermaphrodites, the Coproworm does not necessarily need a partner to reproduce, although it often will if one is available. It releases myriad tiny microscopic eggs into the open sea, and those that hatch can swim around for a few weeks before expiring. Those that do find a host detect it via primitive scent-organs, and immediately latch on with their suckers and begin feeding.