Tardigrade!

Tardigrade!
Image Eye of Science APOD 

"Is this an alien? Probably not, but of all the animals on Earth, the tardigrade might be the best candidate. That's because tardigrades are known to be able to go for decades without food or water, to survive temperatures from near absolute zero to well above the boiling point of water, to survive pressures from near zero to well above that on ocean floors, and to survive direct exposure to dangerous radiations...."
March 6, 2013 APOD 

Bookmarked here because IMHO this is the most striking and educational image so far in the glorious gallery of APOD 2013.