Bryozoans are colony-forming marine animals. The colonies resemble bleached seaweed, a piece of bone cartilage, lace curtain or polyp colonies. A colony of bryozoans starts with one bryozoa, which forms from sexual reproduction. This animal clones itself asexually, whereby copies evolve which together form a colony. This makes all animals in a colony family. They can even form reefs: the so-called 'living stones'. Examples are jelly bryozoan, hornwrack and hairy sea-mat.