The alien is from a highly intelligent species that has developed a spacefaring civilisation. They are sexuate carnvores, have six limbs and generally moves similar to a spider, but can also stand up tall on their two hind legs. They have two long jointed arms that are capable of grabbing objects and throwing them long distances, and can also use their six limbs to climb. Able to breath Earth's atmosphere, they are troglodyte by nature. Gifted with telepathic abilities among themslves, they can also communicate with humans they have physically touched and pôssess some telekynetic talents and are able to interfere with electrical fields.
A ship containing one of these aliens was detected by Sputnik in 1957 orbiting the Earth. It was shot down to Earth in 1958 by detonating a nuclear warhead in the upper atmosphere. The aliens was taken to Area 51 but escaped while being moves to another area in 1979 near Lillian, Ohio. He then managed to reassemble its hsip and left the planet.
Source: Super 8 film.