Hermissenda crassicornis, also known as the opalescent nudibranch or thick-horned nudibranch, is a species of brightly coloured, sea slug or nudibranch, a marine gastropod mollusc in the family Facelinidae.

Hermissenda crassicornis. Retrieved January, 01 2022, from en.wikipedia.org/wiki/Hermissenda_crassicornis.