I had this idea one day (way back in December), and thought "Hey, that might make a good picture." I'm not sure if I succeeded, but I'm thoroughly proud with how it turned out.
The idea had to do with an archeologist uncovering a most peculiar find in an ancient cave, left there as an homage to gods that had been so gracious as to visit the civilization personally: a mural, half painting, half carving, depicting the gods and their most magnificent chariot. Can you guess who they are? Granted, this particular history doesn't fit with the actual Back to the Future universe, but, say, if they made an animated TV show, this is likely somewhere the writers would take the characters.
Maybe you'll get it, maybe you won't, but I greatly enjoyed doing this one, and hey, I got to pay homage to two of my favorite icons from the 80's: Back to the Future and Indiana Jones (the archeologist morphed into him (as I thought he would while drawing it)).