Intelligent alien life is extraterrestrial life that has developed technology and some form of civilization. While it is believed by many that some sort of non-Human intelligent life exists in the universe, it is not actually known for sure.
Most intelligent aliens that have been reported are humanoids, typically the Greys. However, it is unlikely that many extraterrestrial species will have the two-legged, Human-like body plan. Still, there are many other types of alien appearance that have been reported.