Branching Bryozoans (likely Bugula sp.)
Bryozoans (also known as "moss animals") are a phylum of simple, aquatic invertebrates, nearly all living in sedentary colonies that can take the form of fans, bushes, or sheets. Single animals with diverse functions, called zooids, live throughout the colony, including autozooids, which are responsible for feeding, excretion, and supplying nutrients, as well as specialized zooids that store fertilized eggs, defend the colony, or form attachment structures that act like roots. The feeding zooids have a special filter-feeding "crown" of tentacles called a lophophore. Marine bryozoans have many predators, including sea slugs (nudibranchs), fish, sea urchins, pycnogonids, crustaceans, mites, and sea stars.
Marine bryozoans are commonly responsible for biofouling on the hulls of ships, on docks and marinas, and on offshore structures. They are among the first colonizers of new or recently cleaned structures, including the OOI infrastructure. They are frequently seen encrusting the Shallow Profiler platforms and cable connection cages, as well as the top buoys of the deep profiler moorings.
References:
https://en.wikipedia.org/wiki/Bryozoa
https://en.wikipedia.org/wiki/Bugula