Pandoravirus - Aliens among us?
"Scientists have found the biggest viruses known, and these pandoraviruses have opened up entirely new questions in science—even suggesting a fourth domain of life, a new study says.
Each about one micron—a thousandth of a millimeter—in length, the newfound genus Pandoravirus dwarfs other viruses, which range in size from about 50 nanometers up to 100 nanometers. A genus is a taxonomic ranking between species and family.
In addition to being huge, pandoraviruses have supersize DNA: 2,500 genes as compared with 10 genes in many viruses"
Pandoravirus - a fourth domain of life
National Geographic article and Scientific paper