500-million-year-old “squid” were actually ferocious worms

A stunning discovery in North Greenland has reclassified strange squid-like fossils, revealing that nectocaridids were not early cephalopods but ancestors of arrow worms. Preserved nervous systems and unique anatomical features provided the breakthrough, showing these creatures once ruled as stealthy predators of the Cambrian seas. With complex eyes, streamlined bodies, and evidence of prey in their stomachs, they reveal a surprising past where arrow worms were far more fearsome than their modern descendants.