As well as the eyes on its head, it has accessory eyes on the papillae of its back, complete with retina and lens, which let it detect the shadows of predators from above.
From Warty Slug
It is not a nudibranch despite its looks: it is a pulmonate, more closely related to land slugs than to sea slugs. It breathes air with a lung.
From Warty Slug
Its eyes sit at the tips of two head tentacles, and it also has dorsal eyes scattered over its back, which is most unusual.
From Warty Slug
It is hermaphrodite but never self-fertilises, always mating with another individual.
From Spanish Dancer
It eats marine sponges, toxic species included.
From Spanish Dancer
It sequesters toxins from the sponges it eats and puts them straight into its eggs, protecting them from predators.
From Spanish Dancer
Its mating is among the most spectacular in the animal world: the two animals hang in mid-air from a thread of mucus and unfurl bluish copulatory organs that twine around one another.
From Leopard Slug
Beneath the mantle shield it keeps a vestigial internal shell of 13 to 15 mm, all that is left of the shell its lineage lost.
From Leopard Slug

Ecosystems