A very small nudibranch, Limacia clavigera grows to only about 2cms and a close examination will reveal that the yellow-tipped projections around its body are club-shaped. Also on its back the yellow spots are quite raised. It feeds on bryzoans and is often seen feeding on sea mat growing on kelp fronds (as in the picture) with the similarly coloured Polycera quadrilineata. Widespread all around the UK except in sandy and silty areas.
St. Abbs Marine Reserve, Scotland. North Sea