That's slime from the hagfish. Take a good look, because you may be wearing it one day. Anna Rothschild of PRI's The World files this report over at the BBC about how hagfish slime may just be the fabric of the future:
The slime is composed of thread-like fibers.
“When you stretch the fibers in water and then dry them out they take on properties that are very silk-like,” says Douglas Fudge, who heads this research project at the University of Guelph.
Hagfish fibers are incredibly thin and extremely strong, and that gave Fudge and his colleagues an idea.
For years, scientists have been looking for natural alternatives to synthetic fiber like nylon and spandex that are made from oil, which is a nonrenewable resource. [...]
No one has made a spool of hagfish thread yet, but Fudge and his team see a future where hagfish slime or similar proteins could be turned into high-performance, eco-friendly clothing. The fibers might be used for stockings or breathable athletic wear or even bullet-proof vests.