Sea slug egg ribbon (pink) on a coral reef. Sea slugs are also known as nudibranchs. This egg ribbon has been laid by the sea slug Jorunna rubescens. The egg ribbon is usually laid on the substrate on which the sea slug feeds, and usually a larval stage hatches from the multiple eggs contained in the egg ribbon. These larvae will be free-floating (planktonic) and will eventually develop into the adult form. In some species, a small adult form hatches from the egg. Photographed in the Indian Ocean, off Reunion Island.