Jellyfish
Although most jellyfish live well off the ocean floor and form part of the plankton, a few species are closely associated with the bottom for much of their lives and can be considered benthic. The upside-down jellyfish in the genus "Cassiopea" typically lie on the bottom of shallow lagoons where they sometimes pulsate gently with their umbrella top facing down. The tiny creeping jellyfish "Staurocladia" and "Eleutheria" cannot swim, and "walk" around on seaweed fronds or rocky bottoms on their tentacles. Most hydromedusae and scyphomedusae that live in coastal habitats find themselves on the bottom periodically, where they may stop swimming for a while, and certain box jellyfish species also rest on the sea bed in shallow water. Even some deep-sea species of hydromedusae and scyphomedusae are usually collected on or near the bottom. All of the stauromedusae are found attached to either seaweed or rocky or other firm material on the bottom.
Chrysaora hysoscella
The compass jellyfish (Chrysaora hysoscella) is a very common species of jellyfish that lives in coastal waters of the Atlantic and Mediterranean, including near the United Kingdom, Ireland and Turkey. It is also known from the southern Atlantic Ocean from the west coast of South Africa and False Bay It has a diameter of up to 30 cm. Its 24 tentacles are arranged in eight groups of three. It is usually colored yellowish white, with some brown. It usually has 16 markings on the bell resembling elongated v's, surrounding a central brown spot. Its mouth is located at the bottom center of the bell, between 4 larger tentacles. They are known to sting.