Picture a creature with a skull but no true backbone that survives a shark attack by instantly turning the water around it into an explosive, gill-clogging weapon, then dines by absorbing a rotting whale's flesh directly through its skin. It sounds like science fiction, but this very real animal may hold the blueprint for the next generation of body armor.

This episode is a deep dive into the hagfish, the ancient jawless survivor that bridges the evolutionary gap between invertebrates and vertebrates. We unpack its bizarre anatomy, its explosive defensive slime, its rule-breaking internal physiology, and why material scientists are racing to copy a 310-million-year-old chemistry experiment.

• How its slime expands 10,000 times in 0.4 seconds, clogging predator gills, and the knot-tying trick it uses to clean itself
• The bagg ...