They are the perfect pet for someone like me. You can find them almost anywhere (for free) and they are almost impossible to kill through neglect, or any other way for that matter.
Here's the Low Down:
They are about 1mm long and live in water and most easily found on moss.
They look a little like a piglet & move a little like a bear and have claws on all 8 of their feet. Their mouth (or mouthparts) can extend to capture food , which can be plant or animal life that is floating by.
They are cool because they are indestructible. Ok, tardigrades are not undistructable, but they are pretty damn hard to kill. They are most famous for how they basically have a form of stasis that helps them survive in extreme conditions, particularly the lack of water. One of the keys to this process seems to be shedding up to 97% of their 'normal' water content, and replacing if with sugar to protect the cells from destruction by ice crystals, which is why we can't be thawed out if we freeze solid. Once they are covered in water, they rehydrate & plod along quite happily.
|Tradigrade in it's 'Safe Mode'|
No food or water for extended periods,
being frozen for up to 30 years,
temperatures around 150C,
exposure to 10 times the ionozing radiation it takes to kill us,
10X the pressure experienced in the Marianas trench
& they can survive in a vaccum.
|Cool & a little Scary|
If that's not enough they have been around for over 500 million year & have survived unprotected space travel. Plus there is some evidence that they may have up to 17% foreign (non-tardigrade) DNA which is a cool thing all by it's self.
The #1 reason I want one as a pet is this, With powers like that all they need is a little organization & they could take over the world. So I'm going to start being nice to them, just in case.
You can read most of what you need to know at the obligatory Wikipedia link.
I'd also suggest doing an image search, as there are so really cool ones.
If after my sales pitch you too want one, you can learn about the acquisition, care and feeding of your tardigrade here