Scientists collected some moss samples from Antarctica in the 1980s. Recently some of these specimens were thawed and scientists were able to observe a microscopic animal known as the water bear (aka Tardigrade) revive to life. The bear showed movement within the first day but took a few days to fully come out of its slumber and begin reproducing. Scientists believe they are able to survive in this manner by replacing the water in their cells with a protective sugar called trehalose. They also reduce their metabolism to 0.01% of normal.
Water Bears are very common inhabitants of wastewater treatment plants and are also sort of the rock stars as they are easily visible under a microscope and are usually quite actively munching on bacteria.