This is a video of a Tardigrade (Phylum Tardigrada), a microscopic animal.  Also known as "water bears", these organisms are truly one of nature's most amazing sights.  Research has shown that they can survive for years without water and can even survive in the vacuum of space, even when exposed to high levels of radiation!  This is due to a remarkable adaptation, namely the ability to assume an inactive state.  This state is known as a "tun".

They are typically found in dried lichen or moss.  Once exposed to water, water bears will come out of their inactive form.  When I first collected a sample of moss from a tree in my backyard, I found nothing resembling tuns, although there were some strong candidates.  When I checked a day later, I came upon the water bear shown in the video.  It may have been in its inactive state for months or even years.