Japanese scientists semi-successfully revived two tardigrades - also called water bears - after 30 years in a frozen state.
"Tardigrades, also known as water bears, are tiny water-dwelling 'extremophiles,' surviving under hostile environments including extreme temperatures, pressure and even radiation," according to the Wall Street Journal. "They are known to enter a stage known as cryptobiosis under some conditions, in which they slow or shutdown metabolic activities for an extended period."
Researchers at Japan's National Institute of Polar Research collected the water bears in Antarctica in 1983. They were defrosted in 2014.