Ribbon-Tailed Detriti
The Ribbon-Tailed Detriti is a unicellular scavenger/detritivore, replacing its ancestor as a digestive system symbiont of the Vinagob and its descendants.
On the surface, the Ribbon-Tailed Detriti doesn't seem that different from its ancestor. It has two nuclei, a few small, simple, transparent organelles hidden by its nuclei, a thin cell wall (not visible), a long, somewhat flattened rhomboid body, and ten cilia and two flagella. It is slightly more resistant to digestive enzymes, and with its spiral-shaped flagella, it can swim much faster among the mucus of its host's digestive system.
Like its ancestor, it gathers in groups. But only when it encounters a dying organism trapped in its host's mucus does its big difference appear: in addition to being a scavenger, it's a pack-hunting predator. Similarly to the Earth bacterium Myxococcus xanthus, the Ribbon-Tailed Detriti coordinates its movements among hundreds of its kind through simple "rules". For example, if it's in contact with the cilia of another of its kind, it will move in the same direction. Furthermore, it moves towards various chemicals that leak out of prey as their host digests them, such as products of photosynthesis.
Once a pack of Ribbon-Tailed Detriti is close to a dying organism, it will secrete enzymes of its own en masse, finishing off and dissolving the trapped prey. With the help of packs of Ribbon-Tailed Detriti, the host can handle slightly (+0.4 mm in the Vinagob's case) bigger prey, which otherwise would take a while to digest or even escape.
The Ribbon-Tailed Detriti gets energy from food by converting glucose to alcohol, making carbon dioxide as a waste product. Without immediately available food, it extracts energy from oxygen in a process that converts the oxygen to carbon dioxide.
It reproduces by binary fission. If a Ribbon-Tailed Detriti cell happens to float outside its host, such as from being carried through an outflow vent, it thickens its cell wall and enters a dormant state. It can float for several hours. Only when it encounters an environment of about 6.3 pH (slightly more acidic than seawater), will it break down its cell wall and become active again. Often, it becomes active again in another suitable host, and it's frequently an individual that lives nearby. However, its system for recognizing a suitable host is crude, so sometimes it activates only to be devoured by crystalflora.