Over 3 billion years ago, down in the deep sea vents where the earth’s magma moved the dark water, a single-celled organism turned over, and changed.

This tiny organism was LUCA: the Last Universal Common Ancestor.

Millennia passed and LUCA had children, who had children, who moved up from the deep sea vents. As they evolved, LUCA’s children developed traits that divided them into different groups.

Every animal on earth descended from LUCA. The echinoderms became symmetrical: the starfish radiating arms and the sea urchin extending their delicate spines. Arthropods like lobsters and insects encased themselves in strong exoskeletons. Vertebrates like sharks, humans and birds grew spines and hollow nerve cords, becoming shrewd and swift.

And then there are the mollusks, the dazzling, mysterious animals who you’re about to meet.

Straighten your spine, vertebrate. Things are about to get weird.