TheChelidonura hirundinina is not a nudibranch - still, this colourful headshield slug can grow up to 4 cm long, and lives in the western Indo-Pacific. See the little hairs around the edge of its head (closest to the camera)? Those are cilia, and are used as sensors to detect their prey: flatworms. This species is also known as the Swallowtail Headshield slug, because of its split back end.
