Boreolenta maris
Due to B. psycrasapila swimming through droplets in Zone A to parasitize, it is well-adapted for swimming. So if they fell into the ocean, they'd be great swimmers in it. Which did happen, actually- several times. While in Zone 2 and Zone 11 there are no organisms very closely related to its host, Zone 1 has an organism in the same order as its previous host of Arctata formisus- its name is Aquaplortatus invictus. As they are both of the order Plortales, it makes it easier for them to evolve from one to the other. As these marine parasites adapted to the more aquatic environment it gradually speciated into Boreolenta maris.
The 7μm, transparent-colored B. maris parasitizes the roots of A. invictus by digging holes from the ocean to the roots. While they originally did this by just using there head, they have evolved cilia around the front of the cell to dig out dirt and detect roots by byproducts expelled from the roots. When reaching a root, it will produce 2 chemicals like its ancestors. One chemical, nearly identical to its ancestor, is the glue-like substance designed to let it stick onto the root. The other is the cell-damaging (used to be destroying but B. maris produces less of it to allow for A. invictus to die less) chemical that damages cells and exposes compounds, which B. maris takes energy from.
Boreolenta maris has a much lower metabolism and doubles every 20-30 minutes to prevent the death of its host (as if the host dies then the cells on it will die as well), and is far more minor then you'd expect since A. invictus can just grow new cells. Infact, it's arguably rather helpful since it allows for the host to gain more nutrients. The offspring that B. maris creates will dig itself outside of the soil and find somewhere else to attack- sometimes the same plant, sometimes not.