Fewer people know that Reese's Pieces weren't the original choice for that scene. In fact, Spielberg actually wanted M&M's candy to be what lured the little space-man out of the shed. In what may be considered nowadays a colossal mistake, Mars, Inc. decided against allowing the use of their candy because, as the story goes, they "didn't want to associate their candy with aliens."
After the movie launched, sales of Reese's Pieces went through the roof, helping to revive the brand. It turned out that children, who command a good amount of their parent's money, fell in love with the alien and subsequently fell in love with Reese's Pieces.
