Notobryon clavigerum is a species of sea slug, a nudibranch, a marine gastropod mollusk in the family Scyllaeidae.
Notobryon clavigerum Wikipedia
The rhinophoral sheaths of Notobryon clavigerum have a crest which is oriented longitudinally running along the posterior margin and the anterior margin. It terminates distally in a wavy margin. With the exception of the tip, the edges of the dorsolateral lobes are smooth, stand up recurved, and display claw-like pappillae that are small and in a row. There are three of these on the posterior and five on the anterior.
This species is found in the Western Pacific Ocean such as in the waters of Japan.