"Something big is coming soon," 'Back to the Future' producer Frank Marshall tweeted on Wednesday night to the consternation of film fans everywhere. "Can't say anything yet. No one should know too much about their own destiny." Was Marshall teasing an obviously ill-advised reboot to the beloved 'BTTF' film series starring Shia LaBeouf? Perhaps a fourth film, one that featured Marty McFly's time-traveling offspring (also played by Shia LaBeouf)? Probably not! (Not yet at least.) It turns out, he was just plugging a sneaker.