I stumbled across this image of Helicocranchia pfefferri a little while ago - easy to see why this little cephalopod is called the 'piglet squid'!
Image (c) Cabrillo Marine Aquarium.
The Cabrillo Marine Aquarium's news release tells us that these little animals ("about the size of a small avocado") are a deep-water species with a global distribution. The piglet's 'smile' is actually a row of chromatophores, or pigmented organs, more of which dot the transparent body wall - so transparent, in fact, that you can see some of the animal's internal organs. And each of its eyes has a photophore (a light-producing organ) set beneath it.
For some strange reason I am also reminded of the dumbo octopus (Grimpoteuthis sp.).