On August 6 2021, the Facebook page “Premium Internet Curation” shared screenshots of a Twitter thread, the latter pertaining to The Starlight Barking — a purportedly bizarre sequel to the book from which 101 Dalmatians was adapted.
That post included nine screenshots, each a tweet in a June 2 2021 thread by Twitter user @SketchesbyBoze (“Owl! at the Library.”) It began:
So, most people are unaware that One Hundred and One Dalmatians, the novel, has a bonkers sequel called The Starlight Barking.
It has never been filmed. It can never be filmed. It is unfilmable.
Come with me on this journey. (1/8) pic.twitter.com/NzAuvCwAS2
— Owl! at the Library 😴🧙♀️ (@SketchesbyBoze) June 2, 2021
The @SketchesbyBoze account included images alongside some of the tweets. The tweets in the thread explained that the book The One Hundred and One Dalmatians was followed by The Starlight Barking, and went on to focus on the purported plot of the second book:
“So, most people are unaware that One Hundred and One Dalmatians, the novel, has a bonkers sequel called The Starlight Barking. It has never been filmed. It can never be filmed. It is unfilmable. Come with me on this journey. (1/8)” 
“One morning the Dalmatians awaken to find that every human in the world has fallen into a mysterious sleep. But dogs now have super-powers—they can fly, operate doors and machines with their minds, and speak telepathically over long distances. They neither hunger nor thirst.” 
“Pongo ‘swooshes’ to London to meet his daughter Cadpig, who is now acting prime minister. A meeting of the Cabinet is held which consists of the dogs owned by every human member of the Cabinet. The dogs agree that Cruella de Vil must be MURDERED.” 
“DOG ASSASSINS are dispatched to Cruella de Vil’s estate in the hopes of killing her and ending the mysterious sleep. But when they arrive, they find that she is also sleeping. Pongo is now very afraid. Who is responsible for this dark magic?” 
“A mysterious Voice speaks through the television, commanding every dog in London to convene at Trafalgar Square at midnight. The Voice says that it will address every dog in the world simultaneously to make an urgent announcement.” 
“At the stroke of midnight, a SPACE DOG appears atop Nelson’s Column. He explains that he is Sirius, Lord of the Dog Star, and that the earth is going to be destroyed in a nuclear war. Sirius loves earth-dogs and wants them to return with him to his home planet.” 
“Pongo and Cadpig, who are now the de facto leaders of earth dogs, meet with their advisors in the National Gallery. They agree that even if the earth is destroyed, they could never abandon their owners. They will stay on earth.” 
“Sirius accepts their decision with regret. Before returning to his home planet, he warns the dogs that their whooshing abilities will disappear at sunrise. The dogs whoosh home and their owners awaken, totally unaware of the global drama that transpired while they slept.” 
“This novel has everything—magical flying dogs, an alien invasion, a team of dog assassins, the prospect of nuclear war. It’s absurd that Disney has overlooked THIS book while churning out prequels and reboots. you’re leaving money on the table fellas.” 
Google Trends data for the 90-day period ending on August 10 2021 demonstrated a spike in interest for The Starlight Barking on June 3 2021 (the day after the thread was published), and seven-day data for the period ending on August 10 2021 showed sustained interest likely created by the Facebook post on August 6 2021.
The book does exist. It is so well known that Wikipedia featured an entry for The Starlight Barking, a book published in 1967, as a sequel to the 1956 book The One Hundred and One Dalmatians.
The “Plot” section closely matched the content of the popular Twitter thread:
One morning, the dogs find all other living things besides dogs cannot be wakened. No dog is hungry, thirsty, or weak. Doors, gates, and machines operate on command, and the dogs are able to communicate via thought waves to others many miles away. Cadpig, now acting Prime Minister in the humans’ absence, orders her parents to come help her in London, where hundreds of dogs are arriving awaiting her advice.
The dogs discover they can “swoosh”, or hover at tremendous speed over the ground. Pongo and Missis select a squad of fifty Dalmatians, including their adult sons Patch, Lucky, and Roly Poly. They “swoosh” to London, and are escorted by Police Dogs to 10 Downing Street. Cadpig and her Cabinet (the human Cabinet’s dogs) hold a meeting with Pongo and Missis to decide what to do next. Roly Poly makes a friend of George, the Foreign Secretary’s Boxer, and the two set off to adventure together.
Upon arrival in London, the White Persian Cat suggests Cruella, now back in London, must be behind the mysterious sleeping. She leads a group of dogs to Cruella’s house, to kill her. However, Cruella and her husband are just as fast asleep as anyone else, and the animals see she is now obsessed with metallic plastics instead of fur coats. They spare her life and return to Downing Street, where the television comes on and a strange Voice orders them to make sure all dogs are in open, starlit spaces by midnight. The Dalmatians accomplish this via Twilight Barking and thought waves.
In Trafalgar Square, Tommy, the cats, the Dalmatians and the General meet with thousands of other dogs to wait. At Midnight, after a strange euphoric moment followed by a moment of terror, Sirius, the Lord of the Dog Star, appears on Nelson’s Column. He explains to all the dogs that he is lonely, and is offering them the chance to avoid the pain of possible nuclear war in the future. However, they must come with him of their own accord. He assures them the world, when it wakes, will not remember dogs ever existed, and that all dogs will be free and know true bliss in the stars.
Pongo is chosen to make the final decision. He consults with the Cabinet, Missis, and the General. Three stray dogs approach, and tell Pongo that no “lost” dog wants to give up their last chance of finding special humans of their own by leaving Earth. This convinces Pongo and the others to choose their masters over Sirius. While Sirius commends their loyalty to humankind, he is sad that he will have to return to space alone. The dogs promise they will look out for him on nights when the Dog Star is in the sky. Sirius grants them the ability to “swoosh” to their own homes before daybreak, at which time everything will return to normal …
A similar entry appeared on Fandom.com’s 101 Dalmations page. Goodreads hosted pages tracking 24 editions of The Starlight Barking published from 1967 onward, as well as a page for users to log and comment on the book. Its summary read:
Dodie Smith’s The Hundred and One Dalmatians, later adapted by Disney, was declared a classic when first published in 1956. The Starlight Barking, Dodie’s own long-forgotten sequel, is a thrilling new adventure for Pongo and his family. As the story opens, every living creature except dogs is gripped by an enchanted sleep. One of the original Dalmatian puppies, all grown up since the first novel, is now the Prime Minister’s mascot. Relying on her spotted parents for guidance, she assumes emergency leadership for the canine population of England. Awaiting advice from Sirius, the Dog Star, dogs of every breed crowd Trafalgar Square to watch the evening skies. The message they receive is a disturbing proposition, one that might forever destroy their status as “man’s best friend.
The Starlight Barking was also mentioned in passing in a 2008 interview with a voice actress from the Disney adaptation of 101 Dalmations (Lisa Davis), and a Disney archivist (Dave Smith):
Q: Did they ever consider doing the sequel to this book, The Starlight Barking?
Smith: I didn’t know about it. I don’t know that that ever was considered. In fact, Walt keeps telling Dodie Smith in these letters, “Write us another book so we can do another story.” She kept saying that she didn’t have any material.
Davis: But she did say that she had a mouse who was sitting on her desk, collaborating with her. So far they hadn’t written anything but she would keep it in mind. It came to mind, when I first did this picture — which was such a pleasure to work on — it came at a time when the studios were all tightening their belts. Other than the Disney Studios. We were all making dreadful B-movies, C-Movies, D-Movies and Z-Movies. They were one-week-wonders. They were just dreadful. To then come to this studio was a joy because we did it until we got it right here. We did it over and over again until Mr. Disney was happy with it. My very first experience that I had with it — and I had forgotten this until today, actually — was that he brought me to the studio for days just to play with puppies. There was a little bungalow over by the gift shop and I would sit in that bungalow with litters of dalmatian puppies. Just playing with puppies. Can you imagine starting a job that way? What a joy that was! Today, you’re playing with puppies. He wanted me to get the feeling for dalmatians.
An August 6 2021 Facebook post and June 2021 Twitter thread described The Starlight Barking, a purportedly “unfilmable” sequel to the book from which 101 Dalmatians was adapted. The Starlight Barking is well-documented, real, and accurately described in the thread by @SketchesbyBoze.