Nudibranchs are a slug shape. It can have many colours such as reddish pinkish spots and a white backround or orange spots and a purple backround. The soft spikey things are gills. The gills in this photo are whitish purplelish. The two antenae at the right are his sensors, which are like eyes.

It lives on the sea bottom in yellow sponges and coral. Some you find in shallow water and some you find in rather deep water. And because he lives on sponges he feeds on them. It moves by pushing itself along with its tail. It is completely harmless. I did not see one at Jervis Bay but I certainly would like to.

Brooklyn