18 Directors Who Sneaked In References To Their Own Movies

Robert Zemeckis’s 2004 motion capture animation The Polar Express might be a bit uncanny valley, but if you can get past the weirdness you might just spot a connection to his hugely successful Back to the Future trilogy.

It’s a split-second reference, but in a scene set in the titular train’s engine room while it’s en route to Santa’s digs in the North Pole we see none other than a flux capacitor – the very mechanism that allows Doc and Marty to time travel in their DeLorean time machine in Back to the Future.

As The Polar Express has a heart-warming lesson about believing in the magic of Christmastime at its core, maybe Zemeckis is telling us that Santa is indeed real and manages to do all his gift-delivering in record speed thanks to time travel. Or that Doc Emmett Brown is actually Father Christmas … or something like that.