Plumose Anemone (Metridium farcimen)
These large, fluffy-looking white (or occasionally orange) anemones are often found on OOI infrastructure in shallow coastal waters (or on the 2oo meter platforms of the shallow profiler moorings). They have a long, slender column and a lobed and deeply convoluted oral disk with hundreds of short, finely tapering tentacles. These carnivorous anemones can be found in dense colonies on any hard substrate in productive waters within their range, from Alaska to California. Individuals can live for several years, as evidenced by the colony that completely overgrew the medium-power junction box MJ01C at the Oregon Shelf 80-meter site, which became known as "The Sheep" for its fluffy appearance.
References:
https://en.wikipedia.org/wiki/Metridium_farcimen
