Crested Nembrotha

''Nembrotha cristata'' is a species of colorful sea slug, a polycerid nudibranch, a marine gastropod mollusk in the family Polyceridae. This species of sea slug is black with green markings; adults are around 50 mm in length, and they live on rock or coral reefs in the tropical Indo-West Pacific Ocean. Although they mostly eat sea squirts, they also absorb stinging cells from the jellyfish that they sometimes eat; this allows the sea slug to deliver a painful sting to would-be predators.