Arnold
Due to slowly increasing competition over time, a group of Ossurans planii made it to zone 2.
They inhabit zone 2's hydrothermal vents, and while they still possess the ability to filter feed, they can chemosynthesize thanks to internalizing Raikos electra and Simalgearous gastrous. Their shell is now able to resist the high heat, pressure, and acidity of their environment, and they've accumulated iron inside their body as a way to control R. electras electricity, resist the pressure of zone 2, and as a way to weigh themselves down. To defend themselves against muscals, they will collect iron rich sediment and store them within a pellet shaped deposit inside if their body. Once they detect the vibrations of a muscal, they will load one of pellet into their siphons and chemically signal for R. electra to generate high amount of electricity as well as electrically charge the pellet. This will create a pressure that, once released, causes the pellet to be ejected out of the siphon and into the muscal.
When reproducing, colonies will connect their siphons and exchange gametes. Once they've successfully created fertilized zygote, they will incubate the zygotes in their modified reproductive chambers until the embryo have formed a rudimentary shell. The shell is then laced with an outer layer of iron and they are then ejected out of the parent through the same process as the pellets are(and no, electrically charging them does not hurt them because faraday cages although the ejection may kill some). Once outside of the parent, the youngs then dissolve their iron shell layer.