As the truck screeched to a halt, one of its containers slid off, hit an approaching Prius  and spilled its contents. Those contents happened to be thousands of kilograms of live hagfish, also known as slime eels. The result of this 2017 car accident  was an absolute mess: the highway was littered  with wriggling fish and coated in a thick slime that took  the fire department 7 hours to clear. Astonishingly good looks aside, the standout strength of all hagfishes is their slime. In fact, they’re probably  Earth’s slimiest animals. But why be so slimy? Watch and learn. This hagfish has detected a dead fish using its keen sense of smell and the tastebud-like organs  dotting its skin. Revealing imposing rows of toothlike structures, it takes the first bite. A shark glides on to the scene and suddenly lunges. Being caught in the shark’s powerful jaws may seem like a guaranteed death sentence, but the hagfish has some tricks  up its sleeve. The shark’s teeth clench down but there are no bones to crush— only flexible cartilage. And because the hagfish’s skin is so  loosely attached to the rest of its body, the pressure from the bite causes the hagfish’s essential organs to slip out of the way, avoiding damage. This is where being a noodle  in a baggy wetsuit really pays off. Meanwhile, the hagfish also actively repels the shark by spewing a stupendous supply of slime. Around a hundred slime glands line each side of the hagfish’s body. Within them are mucus and thread cells. The mucus cells are packed with hundreds of vesicles of condensed mucus while each thread cell contains  an intricately coiled protein fiber. The hagfish contracts the muscles surrounding some of its slime glands, causing the cells to eject their contents into the seawater. In a fraction of a second,  the mucus vesicles swell and burst, and the protein fibers unravel. Together, they expand to 10,000 times their original volume, instantly creating liters of slime. Because the substance is composed of mucus and reinforced with numerous superfine  and strong silk-like fibers, the slime is incredibly soft yet tough. It lodges in the shark’s delicate gills, and as the shark chokes  and tries to clear the slime, it releases the hagfish. Now, the hagfish is free  from the jaws of death. But it’s in a dilemma of its own doing, trapped in a cloud of its own suffocating slime. So what does it do? Well, it ties itself in a knot, of course. Starting at its tail  and passing its body through, the hagfish effectively wipes away its own slime. Apparently unfazed by the whole encounter, it returns to its meal. When it gets to a tougher part  of the carcass... Voila! The hagfish ties itself  in yet another knot to gain leverage and yank off the meat. The hagfish’s slime is so remarkable that people are trying to emulate it. Currently, a lot of athletic  and safety gear is made from non-renewable petroleum-based fibers. But hagfish slime threads rival  the properties of materials like nylon. And fibers modeled after those  in hagfish slime may present a much more sustainable alternative. Meanwhile, hagfish slime is also being  explored in military contexts as a non-lethal weapon that could be used to stop boats by sliming up their propellers. In addition to mastering the art of slime and knot-tying, hagfish have four little hearts and can survive 36 hours  without oxygen unscathed. Oh, and they also clean the seafloor and cycle essential nutrients  in the deep sea. Proto-hagfish were navigating the ocean’s depths more than 300 million years ago— before dinosaurs roamed  and back when Pangea was still a thing. Having persisted through multiple mass extinction events, hagfish have just about seen it all. And it would appear that they’re still having a wonderful slime.