Martian

These rather creepy aliens are what primitive life-forms believe all extra-terrestrials look like. However, as we all know, there are many other beings that look completely different. For example, Daleks, Slitheen and Grunts. These aliens seem extremely disproportionate. These aliens are usually from Mars.

Another nickname for Martians is Grays, but these turned out to be a completely different race of Aliens altogether. Technically, Martians themselves do not exist, so this species is only theoretical. However, there are two races that affiliate themselves with Mars. One called themselves Ice Warriors and lived in the Icy catacombs of Mars before their species was eradicated by Plague. The other, Alpha Centurians, actually consisted of a terrorist cell of Alpha Centurians tha lived on Mars and staged several attempted invasions of Earth, and gained the nickname 'Grays' from the Humans.

After being infected with a cold (which, to them, was deadly) and getting their asses kicked by Thunder Child the Grays soon left Mars and surrendered to the League fleet waiting in orbit.