Okay, that mandala puffer really threw me for a loop! Reminds me in equal measures of the carrier shell cdn.supadupa.me/shop/851/image… and that crackpot "kraken art" hypothesis: io9.com/5848192/giant-prehisto… (Time-controlling hatred squid indeed!)
I love carrier snails, so much. My uncle has an entire shelf of his seashell collection devoted to them - next time I'm over there I've got to take pictures of the one with plastic junk all over it.