In the jungles of Madagascar, there's a spider that weaves webs large enough to span rivers and lakes—and the silk it uses is the world's toughest biological substance.
Discovered by Ingi Agnarsson of the University of Puerto Rico—who first encountered these webs in 2001 in Madagascar's Ranamofana National Park—the Darwin's bark spider isn't particularly large, only about 1.5 inches long (with its legs outstretched), but the webs it weaves are massive. The main anchor thread can be as long as 80 feet, with the orb pattern of the web covering 9 square feet.
The silk itself is twice as elastic as that of any other spider—and, given that spider's silk has a higher tensile strength than steel, that would make this particular spider's silk the toughest known naturally occurring substance.
Yes, you can start having your nightmares now.