Phyllodesmium longicirrum

Prior to my first dive on Lembeh Resort "house reef" one of the dive staff, Lilian. mentioned to Agus (my guide) that she had seen a "solar powered" nudibranch at a certain spot the day before. Quite frankly I had no idea what she was talking about, and was quite surprised when Agus pointed out the critter in question when he found it.

This is quite a large nudibranch approximately fist sized and around 10cm long

Photographed using a Nikon D300 with 60mm micro lens.