Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Nembrotha aurea - Nembrotha aurea is a species of colourful sea slug a dorid nudibranch a marine gastropod mollusk in the family Polyceridae. It was first described in 2008.
A:
Animal