The Hagfish: The Ocean's Slime-Producing Survivor
The hagfish (Myxine glutinosa and related species) is a jawless, eel-like creature that has remained virtually unchanged for over 300 million years, making it one of Earth's oldest living vertebrate lineages. When threatened, a single hagfish can produce up to five gallons of thick, fibrous slime in mere seconds by releasing protein threads that expand 10,000 times their original size upon contact with seawater—enough to clog the gills of any predator foolish enough to attack. Even more remarkably, hagfish are the only known vertebrates with a skull but no vertebral column, and they can tie their bodies into knots to scrape off their own slime or gain leverage while feeding on dead whale carcasses on the ocean floor.