ALF can be heard laughing at the end of the closing credits in each episode.
In the opening credits (Series 1 - 2) ALF is seen recording a home movie and films each member of the Tanner family.
In the 2nd opening credit (Series 3 - 4) ALF and the Tanner family are seen watching home movies of ALF.
After the closing credits in the original unaired pilot, ALF appears and says to the audience "Be there!".