Not so sluggish

In 25 years of living near the coast and regularly perusing the  shoreline and its rock pools I've never consciously seen a sea slug until today. Low tide exposed the beadlet anemones  and I noticed that one or two were attended by a curious pale pink sausage shaped thing, about 3 inches long, covered with soft quills, with a pair of  tentacles at one end. (Some species of sea slug  look more furry and are known as sea mice.)

They are hermaphrodites and they are  carnivores. Using abrasive radulae this particular sea slug can rasp into the sea anemones which are sitting targets for consumption. In the extra it's possible to see that the surface of the beadlet has been partly scraped away by the sea slug.

Sea slugs are members of the order of invertebrates called Nudibranchia. Although this one looks dull and unappealing many of its relatives are vivid and exotic looking creatures which light up the underwater world like jewels. See here if you find that hard to believe.

Needless to say, although there are numerous species the world over (and more keep being discovered) sea slugs are jeopardised by pollution and climate change. Research indicates that we can learn much from their evolutionary adaptations as long as they survive to teach us.