The mating strategies of two species of barnacle. An actor in a loose, baggy, pale-blue sheet appears and explains that if she were a male semibalanus balanoides, one of 1220 species of barnacle, she would have a shapeless body and be stuck to a rock. To reach and penetrate a nearby female, this male would need a long, long penis. We watch how it works. She shows us another barnacle's method: a male larvae climbs up the side of a sexually mature female, drops himself into her, and degenerates into a sexual organ releasing sperm.