What is the name of this thing found on the rocks at Haikou Bay? Be more detailed!

This, this, this...this marine mollusk is very strange...

First of all, it has no shell; secondly, its body is green and its appearance is very strange...this, this. ..

This, isn’t it a sea slug-like mollusk?

Or, is it a nudibranch mollusk?

(Here you might as well introduce it: it is a shellless relative of snails; these marine animals are usually only 2 to 6 centimeters long and are distributed all over the world, from the bottom of the deepest and darkest oceans to the warmest They can survive in shallow water. There are more than 3,000 species of nudibranch molluscs. Scientists estimate that we have only discovered half of these animals. The characteristics of soft bodies and short lifespan of 1 year make many species of nudibranch molluscs. The animals disappear without a trace. Their eyes cannot see anything, and they use their sense of smell, taste and touch to find corals, sponges, eggs, small fish and other similar species in their surroundings for food.)

Of course, I am not very sure...LZ should check the "Illustrated Book of Marine Animals - Marine Molluscs"...I hope you can finally find the answer~! O(∩_∩)O~