A very strange looking slug, it looks much like a sea anemone with a lid! It is circular with tough warty skin and a shell cap. Around the edges of the shell cap there are layers of tissue (periostracum) that looks like a fringe. The whole shell cap with its fringe looks like an umbrella. The slug is usually yellow/orange or red or purple.

Most common subtidally, but can be found in the low intertidal amongst sponges. Although found worldwide, in NZ the umbrella slug is found mainly on the northeastern coast.

This slug is a predator feeding on sponges.