This picture shows a barnacle penis extended from one animal to the other. The other picture shows the barnacle feeding by capturing plankton. Barnacles
belong to the
phylum Arthropod. Barnacles are sessile as adults but
develop from free swimming larva.

This video shows barnacles feeding and mating. They quickly open, extend the feeding apparatus and sweep the water for plankton. Most are barnacles are hermaphrodites that possess both male and female reproductive systems. However, they cannot usually fertilize themselves.