Alien Life: What Does it Look Like?
Speculation has ranged widely over the past century as to what forms life on other worlds might take. The directions such speculation takes generally fall into two categories: Potential lifeforms that might evolve based around the scientific data for a given alien exoplanet, and lifeforms that might evolve given a known branch on the tree of life as found on Earth, extant or extinct.
The type of alien that some conspiracy theorists insist was found in the wreckage at Roswell falls into a category called “Grays”. These are considered an entire classification unto themselves at this point, as they have proven to be a mainstay in science fiction as well as in the public consciousness and interviews with people who claim to have been abducted by aliens.