Spielberg and Lucas: Mastodon fans?

So Shia LeBeouf revealed the title of the new Indiana Jones movie last night at the VMAs: Indiana Jones and the Kingdom of the Crystal Skull.

First reactions: not really a great name for an Indiana Jones movie really; it sounds more like a Dungeons and Dragons campaign or the new WoW expansion pack or a playset you got for your He-Man action figures. But whatever. We recognized that "Crystal Skull" business from somewhere...