http://www.newsweek.com/hagfish-slime-explodes-choke-predator-deploy-military-synthetic-version-1292112

Hagfish are deep-sea eel-like creatures that, when attacked, produce a slime that explodes out to choke their assailant. The slime forms from a small amount of mucus that is ejected from the creature’s glands. As it enters the water, it expands by a factor of around 10,000 and turns into a mass that clogs up the gills of its predators.

The slime is of interest to scientists as it extremely strong, stretchy and very thin. If researchers could develop a synthetic version, it could have far-reaching applications—especially for the military. The U.S. Navy is currently investigating its potential as a form of defense.