Pyura spinifera

Pyura spinifera, commonly called the sea tulip, is a species of sessile ascidian that lives in coastal waters at depths of up to 80 m. As with almost all other ascidians, sea tulips are filter feeders. The common name comes from the organism's appearance - that of a knobbly 'bulb' or flower attached to a long stalk. Sea tulips come in a variety of colours, including white, pink, yellow, orange, and purple. The coloration of sea tulips depends upon their association with a symbiotic sponge that covers their surface.