A red sea anemone with long, flowing tentacles extending outward, anchored to the sandy sea floor.
image
Cerianthid
This cerianthid or tube anemone was imaged during Dive 03 of the 2026 Cook Islands ROV Exploration cruise. Tube anemones have an elongated body and two crowns of non-branched tentacles. They are known for the ability to make a quick retreat, rapidly retracting their entire bodies into their tubes when alarmed.
Credit

NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration.