This has to be one of the prettiest little gastropods on earth, or at least in the Indo-Pacific/Hawaiian and Christmas Islands where it is found, or maybe just in South Kihei.  I mean, who gets to be lime/blue green with orange and white markings?  I still have yet to see one, so these photos were graciously gifted by a friend who was snorkeling in South Kihei, Maui.  They are fairly uncommon, but like many other bubble shells they can proliferate in certain years in certain areas.  These animals are relatively small (just over an inch or 30 mm) when stretched out of their shells (but who would do that?).  Cory Pittman and Pauline Fienes provide more detail and links to images of two similar looking bubble shells, so if you’re wondering why your individual is really tiny, has more purple spots or more prominent orange ones, check their site out.