The Palmyra Atoll is about 1,060 miles south of the Hawaiian archipelago in the equatorial Pacific. Far from any permanent human disturbance, it is a haven for an astonishingly diverse spectrum of species, but for the past couple decades, the reefs have been overrun by creatures we know very little about: corallimorphs. Corallimorphs are cnidarians, like hard corals, sea anemones, and jellyfish. They’re closely related to corals, except without the hard parts, and in Palmyra they’ve been outcompeting and even actively killing their cousins—smothering them like a blanket and throwing…
