This is Chromodoris kuniei. I believe you've met before.
The photo is by Mia Arisanti.
Thanks to a bout of insomnia, I spent last night switching over to the new Blogger. I lost all my changes, and I didn't much like Blogger's layout ideas, so I had to attempt a variety of hacks and workarounds to get things up and running today. I'll be changing things around further as time allows.
That said, those who wish to relieve the Dear Dead Days can now click on the "nudibranchs" tag below, and view dozens of 'em on one page. I'll eventually add tags to the other posts, too (assuming I can figure out what, if anything, they're about).