Hagfish slime is made up of two key components: mucus and fibers. The mucus bit is pretty self-explanatory, but the fibrous part is a little more complicated. Slime fibers are wrapped up in skeins, which look almost exactly like skeins of yarn (except they're the width of two human hairs). These balls of fiber unravel, and it's this motion that helps the goo expand to 10,000 times its previous size in just a few tenths of a second. Previous research had shown that the skeins can uncoil without much outside help, but it's not like they're spring-loaded or anything. If left relatively undisturbed they'll eventually unravel all the way, but it takes much longer—on the order of minutes—than it does during an attack.