One of the great mysteries of the microscopic animals known as tardigrades is their uncanny ability survive almost anything: extreme heat, extreme cold, desiccation or drying out, and even the vacuum of space. Now, we are a little closer to understanding how they do it. The key, at least for surviving desiccation, is a special protein that tardigrades use to replace the water in their bodies with a form of glass.

Tardigrades are also known as water bears, and they normally live in moist, mossy environments. But when those environments dry up, tardigrades go into a state known as “tun”—it’s a kind of suspended animation, which the animals can remain in for up to 10 years. When water begins to flow again, water bears absorb it and return to life.

Tardigrades aren’t the only creatures who do this. Brine shrimp and certain kinds of worms can also dry up and come to life again. But what makes tardigrades different is that they use a special kind of disordered protein, unique to these animals, to literally suspend their cells in a glasslike matrix that prevents damage.