Robust Sea Cucumber

Thanks AlbertKang for the identification.

Yes, lots of new Divers mistaken them for Nudibranch due to its size and see the tentacles withdraw like Nudibranch.

Wow! Now I understand theweird spikes :-)

This one is not a Nudibranch, but Sea Cucumber.
Lots of them all over Anilao, in the thousands :p

Ok Marta, thanks.

This is a challenging case for me. As for color I could say Aegires citrinus but it has spikes like Dendronotids. Perhaps you can find help by posting this spotting in the Sea Slug Forum:
http://www.seaslugforum.net/