Steven Spielberg's charming family film didn't receive any money to use Reese's Pieces candy, just free sweets to use in the shots. (They had approached Mars for their M&Ms but they declined.) Elliot makes a trail of Reese's Pieces to lure the alien home, prompting sales to jump through the roof up 80%. E.T. is at it as well, seen later in the film swigging Coors beer!

He obviously settled into American culture very well indeed, because he returned to his home away from home to front a Coors ad.