Gordon Shumway, is saved from his doomed planet, Melmac, by flying throughout the Andromeda Galaxy to the Milky Way galaxy.
After a couple years, he crashed landed on Earth at the top Roof of the Garage of the "Tanner family".
Over the 3 and half years, ALF was taken care of by The Tanners.
The Tanners always tried to hide him from the Outside world, until he was found on the Last Episode of the TV Series by the Alien Task Force.
In 1990 there was a movie call "Project: ALF".