Pandoravirus is the largest virus ever discovered on Earth. It is more than 1000 times larger than the common flu virus, measuring approximately 5000 nanometers in size, and is so large that scientists in the past have confused it with a bacterium, which are much larger than viruses. Some researchers believe that Pandoravirus may have originated on another planet, possibly Mars, however this belief is not shared by all scientists familiar with the virus.
Because Pandoravirus has only recently been identified, whether or not it is dangerous to humans is still unknown. Viruses infect living organisms by burrowing into cells larger than themselves, then releasing a viral payload that forces the host cell to produce more virus cells. Viruses are continually evolving, meaning their exact nature is changing all the time in response to their environment.
Pandoravirus is huge in more ways than one.
While common cold or flu viruses usually contain less than 15 genes (these genes make up the genetic program that is the viral payload that virus cells carry), Pandoravirus contains over 2500 individual genes in it's viral payload. Incredibly, only 6% of the genes found in Pandoravirus are similar to genes found on Earth. This means that nearly ninety-five percent of the genetic payload found in the giant virus is considered alien - unknown genetic material. This is why some scientists believe that Pandoravirus originated on another planet.
At this point in time, Pandoravirus has only been discovered underwater, and scientists do not expect the virus to be found on land.
Currently, microbiologist Jean-Michel Claverie and his partner Chantal Abergel have identified two species of Pandoravirus: Pandoravirus salinus, found in the Tunquen River in Chile, and a second variant named Pandoravirus Dulcis, taken from a pool of freshwater in the region of Melbourne, Australia.
Scientists say that they expect more extremely large viruses to be discovered, now that Pandoravirus has been identified as a virus and no longer mistaken for a misshapen form of bacteria.
While the virus is considered harmless to humans, "never say never" is the overall message in regards to Pandoraviruses' possible communicability and danger to health.
Pandoravirus is bigger than a flu virus, but smaller than a football. It is a hideous, greenish thing with chunks of weird stuff floating inside it's mucous-y, membranous body. It has no discernible head, face, or buttocks, and emits a nanomolecular stink that repels all unfortunate enough to make it's acquaintance. Avoid at all costs.