Long live the Tardigrade!
Tardigrades, also called "water bears" or "moss piglets" are a "phylum of eight-legged segmented micro-animals (Wikipedia)." Tardigrades are almost microscopic (0.5 mm on average) and extremely resilient. They can survive extreme conditions all around the planet and can live in severe temperatures and pressures, air deprivation, radiation, dehydration, and starvation. — Read the rest
