We’ve heard of a “Yellow Submarine.” But “Green Submarine”? Well, Sir, that’s simply a step too far. On Thursday, March 18, Paul McCartney announced that he is releasing a picture book called Grandude’s Green Submarine, which is actually an “exciting sequel” to his 2020 picture-book debut, Hey Grandude! At no point in the Penguin press release or McCartney’s announcement tweets is there any mention of the aforementioned brightly colored submarine for which the Beatle is already known. Does McCartney think he’s fooling us? Does he think he’s getting away with something? Was the “Yellow Submarine” given a green coat of paint for Grandude’s adventures, or is it a different sea craft entirely? If the latter, which submarine would win on the naval battle stage: yellow or green? The existence of Grandude’s Green Submarine raises a thousand questions too complex to answer. We’ll have to wait until the book is out in September 2021 to know the truth.