Here's a quick one minute video demonstrating the slime power of the hagfish. The animal is anesthetized, given a small pulse of electrical current, and when the tiny bit of slime extracted from it is put into a glass of water, well... You've Been Slimed!
Hagfish aren't really fish, as they have no jaw. In fact, they're the only animal that has a skull and no vertebral column. Their slime is believed to be used primarily as an escape mechanism. They secrete it when captured, but it is also believed that they use it as a lubricant to free themselves from the carcasses on which they feed. The slime also acts to clog up the gills of predator fish, and so the hagfish has developed a peculiar way of keeping its own gills free of slime. When agitated, the hagfish secretes enough slime to turn a 20 liter bucket of water into pure slime in a matter of minutes. To clear itself of this immense amount of slime, the hagfish ties itself into a knot, which then travels the length of its body, thereby wringing out the slime, and likely freeing it from its captor.