Spider silk is an undoubtedly tough material. Just last year, a zoologist from the University of Puerto Rico discovered that the webs of C. darwini, or Darwin's bark spider, are twice as elastic as any silk from other web-weaving spiders and are 10 times better than the fiber material Kevlar.

Jalila Essaidi, of the Forensic Genomics Consortium in the Netherlands, along with contributors from other research institutes in the Netherlands and the U.S., have developed a "bulletproof" skin that was originally an art project that demonstrated the "relative concept of safety."

To make the patch of skin, Essaidi used a brand of spider silk that came from Utah State University. The silk is a result of genetically modified goats and worms, where the spider silk protein is harvested from the goat milk to make ultra-strong fibers. 

Essaidi then obtained human skin cells from Leiden University Medical Center in the Netherlands.

The spider silk and human skin cells were combined to create the "bulletproof" patch of skin. While this piece of skin is somewhat bulletproof, it cannot repel fast-moving bullets. For instance, it was pierced by a bullet shot at normal speed from a .22 caliber rifle, which is the standard level of protection for a Type 1 bulletproof vest. However, the patch of skin was able to prevent the penetration of a bullet shot at lower speeds (the researchers conveniently didn’t report the how fast the “lower speeds” were).

"Even with the 'bulletproof' skin being pierced by the faster bullet, the experiment is, in my view, still a success," said Essaidi. "The art project is based on and leads to a debate on the question, 'Which forms of safety are socially important?"

This skin shield could someday be improved and used for military use on the battlefield, as well as other forms of protection. But for now, this patch of skin is on display at the National History Museum Naturalis in Leiden, Netherlands until January 8, 2012.