About Them

These little ones are tiny, like, A LOT! Most of them are between 0.3 and 0.5mm! The largest species can reach 1.2 millimeters. That is, if you see one of them, look for an ophthalmologist (and a psychiatrist, preferably).
If you've seen Ant-Man and the wasp, you must have seen them.

Extreme rules!

Have you ever taken your body to the extreme? Why they already! Check out what they do:
They can survive minutes heated to 151°C and a few days cooled to 200°C!
They can withstand vacuum pressure and very high pressures!
They can withstand decades of dehydration! Can you imagine going 30 years without taking a sip of water?

Let's go to the moon!

These little ones can withstand lethal doses of 5000 gamma rays (yes, the same one that turned Bruce Banner into a hulk) and 6200 heavy ion rays. If a human being has contact with at least 5 heavy ion ray, one will not have good news.
And yes, they can go to outer space and, amazingly, to the moon (without any spacesuit). They are born astronauts!