Tardigrada is a phylum of amazingly resilient organisms found all over our planet. They only need a bit of water to survive wherever they are, but if that disappears then it's not a problem. Water bears, as they are affectionately known, simply enter a dormant state in which they lose much of their body moisture and stay that way until conditions are more favorable.
So smitten are we with these tough little creatures, that NASA has even launched them into space. So what were the results? Well for one they can survive in a total vacuum and exposure to intense UV radiation. That's in addition to being able to survive at temperatures near freezing, above boiling and extreme pressure.