What keeps the boneless, jawless hagfish thriving after more than 300 million years? SLIME. The goop it exudes – a mix of mucus and special protein cells – expands to 10,000 times its original volume in less than half a second, potentially clogging the gills of competitors and predators. | Deep Look • PBS

The hagfish is a slime-emitting ocean-dweller that's remained unchanged for 300 million years--and it shows. It has a skull (but no spine), velvet smooth skin, and a terrifying pit of a mouth that’s lined with rows of razor-sharp teeth. 🎥Crazy Monsters | Smithsonian Channel