At the edge of Cape Town’s city lights, one of the ocean ’s most intricate ecosystems is held together by creatures most people have never seen. Here, beneath the swaying kelp canopy of the Great African Seaforest, a helmet snail rises from the sand, siphon probing like a periscope for the scent of sea urchins. It disarms their prickly spines with slime and liquefies their innards with acid, keeping the grazers in check and the forest from being devoured. The snail, in turn, must evade the