A sea anemone, e.g., is a type of POLYP, which is a small, soft-bodied invertebrate that lives in the ocean. They are typically found attached to rocks or other hard surfaces and have a column-like body with tentacles surrounding their mouth. Sea anemones are part of the Cnidaria phylum and are related to jellyfish and coral. They feed on small fish and plankton and can range in size from a few millimeters to over a meter in length.