The concept of the ‘Easter Egg’, that is, a hidden detail intentionally placed into a film for keen-eyed viewers to find and use to improve their nerd-cred, came about in the 70s. Many mis-attribute its origin to a bit of trivia from The Rocky Horror Picture Show set, where cast and crew staged an actual Easter egg hunt but couldn’t find all wayward eggs before shooting was due to start. This led to some chocolate eggs still being visible in the final cut. It’s an interesting story, but not where the term came to be.