The Ghost of Mark Twain and His Copyrights

In 1910, Samuel Clemens, the author who went by the name Mark Twain, died.
This was during the age of Spiritualism--the popular belief that it's possible to communicate with the spirits of the dead through mystical rituals, such as seances. 7 years after Twain died, Emily Grant Hutchings, a journalist, announced that the ghost of Twain had dictated a novel to her through a ouija board. It was titled Jap Herron. Hutchings published it.
The estate of Mark Twain said it owned anything Twain wrote--even while dead--and therefore sued Hutchings for copyright violation. Thus began one of the strangest copyright lawsuits in American history. Parker Higgins writes at Fusion:

Twain’s estate, while skeptical that the book was really authored by the deceased author, said that, if it were, the estate owned the rights to it and publisher Harper & Brothers had a contract to publish it.
At the heart of the case were some novel legal questions: Can the law recognize a dead person as the author of a new work? And if so, could Twain’s ghost (or its human mouthpiece), wiggle out of Twain’s agreement with Harper & Brothers to publish all of his books? Finally, even if those copyright hurdles could be cleared, what about using Twain’s pen name, which the publisher held as a registered trademark? (Twain’s legal name was Samuel Clemens.) […]
So the more firmly they insisted Twain himself was behind the work, the more they strengthened the Twain estate’s copyright argument that it, as the owner of all things written by Twain, owned this book, too. And Twain had a deal with Harper & Brothers that gave it the sole rights to publish books by Twain, so Hutchings and her publisher would have to produce credible evidence that he wanted to break that deal in his afterlife.

Jap Herron, which was probably ghostwritten by Hutchings herself, is now indisputably in the public domain. You can read it here.