I know Hoover's Hawaii's Sea Creatures doesn't list all Hawaiian mantis shrimp, but this does look a lot like the Ciliated Mantis Shrimp (Pseudosquilla ciliata), supposedly the most frequently encountered species. It was only 10-15 cm long, and I only got a few seconds to observe it before it fled back under the coral. After reading about their ridiculous visual capacities, though, I don't feel so bad: three focal points per eye, 16 different visual pigments, polarized light sensitivity, etc, etc. Hoover writes that those species that smash the shells of their prey can often crack the walls of aquaria, and that larger specimens that impale their prey (as this one does) can sever human fingers. Did I mention that they're exceedingly intelligent?

I think I'm in love.