Nembrotha kubaryana, also known as the dusky nembrotha, is a large dorid nudibranch native to tropical Indo-Pacific reefs, where it is usually found crawling over coral rubble and rocky substrates. Its black body with vivid green markings and bright orange rhinophores and gills signals toxicity, a defence gained by feeding almost exclusively on certain ascidians from which it sequesters chemical compounds. Adults can reach around 10 centimetres in length, and like other nudibranchs it is a hermaphrodite, engaging in reciprocal mating before laying distinctive ribbon-shaped egg masses.