Thomas and Twilight Sparkle's Adventures of 10,000 BC is an upcoming Thomas/MLP/Warner Bros. crossover to be made by Hiatt Grey.
In about 10,000 BC, a tribe of hunter-gatherers called the Yagahl live in a remote mountain range in the Urals and survive by killing woolly mammoths. The camp is led by a hunter who has proven his bravery by killing a mammoth, and taking the White Spear. The people also strongly venerate an elderly woman, called Old Mother.
D'Leh, a young hunter, while hunting mammoths, manages to kill one and wins the White Spear. He also wins his companion Evolet in marriage. Horse-raiders attack the camp, enslaving Evolet and several others. D'Leh and three companions rescue Evolet, but she is recaptured with two of the companions. D'Leh and Tic'Tic, the remaining companion, continue on and learn of a prophecy from a tribe they meet: whoever talks to a Smilodon that they call the "Spear-Tooth" will help free their people. D'Leh realizes the prophecy was about him.
Several tribes agree to form a coalition to pursue the raiders. They find the ship holding Evolet. With no means to follow the ships, they journey through a vast desert, discovering an advanced civilization similar to ancient Egypt, ruled by an enigmatic figure known as "The Almighty". Tic'Tic dies from injuries sustained in a fight with the guards before they can raise the alarm. The Almighty's priests believe that Evolet is destined to kill The Almighty. D'Leh starts a rebellion among the slaves.
The Almighty offers Evolet and the other hunters to D'Leh in exchange for abandoning his rebellion. D'Leh feigns acceptance of the deal but throws a spear at The Almighty and kills him. During the ensuing battle, Evolet dies, but is restored by the Old Mother sacrificing her own life. They bid farewell to the other tribes and return home.
- Princess Celestia, Princess Luna, Knockout, Puffer, Dolphy, Rachel, Mighty Joe, Jenny, Pete, Kevin, Blythe Baxter, Zoe Trent, Pepper Clark, Penny Ling, Vinnie Terrio, Sunil Nevla, Minka Mark, Russell Ferguson, Gail Trent, Mitzi, Buttercream Sunday, Sugar Sprinkles, Team Griffin/Eeveelution, the Griffin Family, Vinny Griffin, Glenn Quagmire, Cleveland Brown, Joe Swanson, Belle, Ariel, Princess Jasmine, Princess Anna, Queen Elsa, Judy Hopps, Nick Wilde, Joy, Sadness, Anger, Fear, Disgust, Little Bear, Duck, Cat, Owl, and Hen guest star in this film.
- Alter, Samantha & Slate, Diesel 10, Den and Dart, Trixie Lulamoon, Discord, Queen Chrysalis, Diamond Tiara, and Silver Spoon will work for the Almighty in this film.
- This film marks it's first appearance of Barret Barricade.
- Thomas & Friends: The Great Discovery and 10,000 BC were both released in 2008.