Tardigrades, also known as water bears, are some of the most fascinating animals in the world because they can live happily in the most extreme conditions. The small, segmented animals come in many forms - there are more than 900 species of them - and they're found everywhere in the world, from the highest mountains to the deepest oceans.read way more here.
Boil the 1mm (0.039 in) creatures, freeze them, dry them, expose them to radiation and they're so resilient they'll still be alive 200 years later. Water bears can survive being heated for a few minutes to 151 C ( 304 F), or being chilled for days at −200 C (-328 F), or for a few minutes at −272 C (-458 F). They can hack 5,700 grays of radiation, when 10-20 grays would kill humans and most other animals. The animals can also live for a decade without water and even survive in space.