Arachnophobia is one of the most common anxiety disorders, but if we can set our heebie-jeebies aside we can recognize how cool spiders are. And one of the coolest things about these arachnids is the webs they weave.

Spider webs are widely known to be five times stronger than steel and Kevlar. Some can be stretched up to 150 percent. But the question of how a spider converts a liquid into a super-strong material to catch its prey remained a mystery.

A recent paper published in PNAS Nexus reveals that spider-silk proteins don’t just float around randomly before turning into fiber. Rather, they briefly form tiny tube-like shapes that measure 3-4 nanometers in diameter in solution.

These tubes are not only small, they are flexible and unstable enough to remain dissolved. They quickly organize and lock together when the spider begins to spin its web.

The proteins are mostly floppy, but a small amount keeps the tube shapes in reserve.

Understanding this interplay could lead to exciting materials-science applications in self-assembling material design and synthetic fiber.

More like this: Zombie fungus hijacks British cave spiders