The filmmakers originally wanted Elliott to tempt E.T. with M&M's candy. The M&M's people passed since Universal wouldn't let them see the final script. Fast-forward to the film's release, and Reese's Pieces saw a 65% spike in profits. That one's on you, M&M's. (Source.)

E.T.'s face is modeled after Carl Sandburg, Albert Einstein, and a pug. (Source.)

A sequel to E.T. was planned and then abandoned. In it, Elliott and his friends get kidnapped by an evil, mutant race of extra-terrestrials, and E.T. has to save them. Its title? E.T. II: Nocturnal Fears. Catchy, isn't it? (Source.)

Foley artist John Roesch used a wet T-shirt stuffed with Jell-O to simulate the sound of E.T.'s wobbling walk. (Source.)

E.T. may have been a hit, but its Atari 2600 video game adaptation is considered one of the worst video games of all time. In fact, it was so bad that Atari buried thousands of unsold copies in a New Mexico landfill as a tax write-off. (Source.)

One of the early drafts of E.T. had E.T. using his healing touch on Dallas's J.R. Ewing, who had just been shot. (Source.)

E.T.'s voice was recorded primarily by Pat Welsh, an elderly woman with a two-packs-a-day cigarette habit. To create E.T.'s complete "voice," sound effects artist Ben Burtt also used recordings from sixteen other sources including horses, raccoons, sea otters, his wife asleep with a cold, a burp from his old film professor at USC, actress Debra Winger, and Steven Spielberg. (Source.)