Seeing as today is the anniversary of when Doctor Who first premiered, I feel like this might be a good time to share an idea I've had recently for a crossover fanfic of Land Before Time with Doctor Who.
Which version of the Doctor would this story involve? That's what I think makes this idea a little fun. This story idea would cover multiple entries in the LBT series, with the version of the Doctor at each part being contemporary to whoever was the "current" Doctor at the time those different entries had originally released.
Act One would have the Seventh Doctor (and his companion Ace) get involved in the events of LBT 2. They would at first observe from a distance, astonished to see talking dinosaurs, but after the chaos of the egg theft and rockfall from the Great Wall forces them to meet Littlefoot and his friends, they decide to help the kids care for the egg they found and believed to have rescued from the egg thieves. The Doctor even offers to use some kind of incubator inside the TARDIS to help that egg, leading to an amusing scene where the five young dinos first see the weird blue box that's bigger on the inside. When Chomper hatches, four of the five kids flee, but the Doctor is able to close the TARDIS door to trap Littlefoot and help him understand how harmless the hatchling Chomper actually is. When the egg eaters pursue the other kids, Littlefoot goes to help his friends and the Doctor (with Ace and Chomper) soon follow. After a few more wild chases throughout the Great Valley, two sharpteeth arrive to attack, and soon after the adult dinos arrive to fight them off. Since the presence of the TARDIS also functions passively as a universal translator, both sides of the battle would be able to understand each other, resulting some amusing banter back and forth. Eventually, it's revealed that the two sharpteeth are actually Chomper's parents, who agree to leave the valley once the others allow Chomper to go with them, with the Doctor offering to escort them out of the valley. As the sharpteeth are about to leave, they encounter the egg eaters trying to get revenge on Littlefoot, so to save the young longneck, the Doctor convinces Chomper's parents to go after "the ones who took away your child" and they chase the egg eaters out of the valley. After letting Chomper leave with his parents, Littlefoot and the Doctor help the valley residents refill the hole in the Great Wall. With the adventure concluded, Ace and the Doctor say goodbye to the five young dinos and depart in the TARDIS. After departure, the Doctor confesses to Ace that he knew all along that Chomper's egg was not the one the egg eaters had taken and he discretely returned the egg that had actually been stolen, with his reason for the deception to teach the children a valuable lesson about responsibility.
Act Two would have the Eighth Doctor (at a time when he did not have any companions traveling with him) get involved in the events of LBT 7. Like his previous visit, he initially observes from a distance, but as he overhears some of the advanced knowledge being shared by the two Rainbowfaces, he suspects they are much more than merely another pair of common dinosaurs. When the Great Valley council gathers following Ducky's kidnapping by Pterano, the Doctor steps forward to reveal he has returned, explaining the confusion over his completely different appearance as, "Timelords don't die. Instead, we regenerate." Once the bickering council eventually realizes the kids have run off to save Ducky themselves, the Doctor offers to follow after them himself, assuring the worried adults that "I have my ways" to quickly catch up to those five young dinos. He uses the TARDIS to go directly to Threehorn Peak just in time to see the kids get flung out of the mountain to finally reach the Stone of Cold Fire. Pterano and his goons arrive to take it's power, but soon realize it actually has no power. When the mountain then begins to erupt, the Doctor rushes the kids and even Pterano into the TARDIS and uses it to take them out of danger and directly back to the council site. Later than night, the Doctor finally gets to privately meet with the Rainbowfaces, and after a brief conversation, they come to a mutual understanding that both sides are extraterrestrials who wish to keep some secrets from the other. Before leaving the time of the dinosaurs, the Doctor takes a quick detour to meet with the now exiled Pterano to discus the flyer's improved change of heart. The Doctor even offers to let Pterano travel with him with the promise they could skip through time directly to the end of his five year banishment, but Pterano politely declines as he feels that would be cheating his deserved punishment, to which the Doctor acknowledges as a wise choice.
Act Three would have the Tenth Doctor (and his companion Dona Noble) on a rather special adventure with the young dinos at a time very shortly after the events of the LBT TV series. Unlike his two previous visits, the Doctor decides to just step forward and reintroduce himself to not just the five familiar kids but also Chomper and their new friend Ruby. They soon discover the Rainbowfaces have returned for reasons those two refuse to explain. While the Eighth Doctor had been content to let secrets be kept, the Tenth Doctor is eager to expose the truth about those alien visitors and even invites the seven young dinos along with him, much to Dona's protests for common sense. After many tries with various gadgets, the Doctor is finally able to track the Rainbowfaces and uses the TARDIS to pursue them into a space station orbiting the Earth. The group step out of the TARDIS and begin exploring the alien space outpost, soon getting separated and caught up in several misadventures. Eventually, the Doctor is brought to the authority in charge of the station, who reveals that the operation is a scientific mission to induce intelligence into the primitive creatures of Earth and observe if any of the various species could potentially develop a new civilization, However, the Doctor bringing those seven dinosaur children aboard has threatened to completely skew the results of the experiment, and risks terminating the project via a directed asteroid strike to wipe out all of the affected creatures before they could become too advanced and become a possible threat to the aliens. Once the group is finally reunited, the Doctor reluctantly gives the seven children two options: stay with the aliens for the rest of their lives and never be allowed to return home, or have their memories of the space station completely wiped away so they can return home without being able to reveal the truth to anyone. After a difficult discussion, the kids decide they would rather return home, so they agree to have their memories of the space station erased. When the kids reawaken in the TARDIS with their last memory being in pursuit of the Rainbowfaces into space, the Doctor sadly explains to them that while he did get the answers he wanted, he can't reveal the truth to them as "That would be telling." When the TARDIS returns to the Great Valley and the kids step outside, the Doctor does assure them that, "While I can't just give you the answers to the universe, that doesn't mean I can stop you from trying to find those answers for yourself. You and your future children have a very long journey ahead of you, so you better get started." As the TARDIS departs, Dona admits that what she just witnessed was one of the bravest things she's ever seen the Doctor do.
Act Four would have the Thirteenth Doctor make a special visit sometime after the events of LBT 14. While her companions (Ryan, Graham, and Yaz) spend some time with the seven young dinos, the Doctor leaves in the TARDIS to "have a chat with some old friends." She returns to the alien space station to meet with the commander who had sent a signal to the TARDIS. The alien commander shamefully reveals that after several close calls with the various dinosaurs of Earth (not just the Great Valley), all funding for the massive experiment has now been terminated, and they are thus now obliged to direct that asteroid strike to prevent "unnatural contamination". Not wanting their efforts to go completely to waste, the two aliens who had personally observed the Great Valley were able to compile a complete record of the adventures of Littlefoot and his friends, in hopes that a future "authentic" civilized race might one day learn about some of the remarkable things that once took place on Earth. The Doctor agrees to deliver the records to the humans in the future, but only on the condition that they delay the asteroid strike long enough to allow at least a few more generations of dinosaurs after Littlefoot and friends to continue living, to which the alien commander agrees. The Doctor returns to the Great Valley to pick up her companions and they bid one final farewell to the seven young dinos. After the TARDIS departs, the Doctor reveals to her companions the device containing the records and that she has been asked to "deliver a very special package. One that cannot be given to someone, but rather must be found by those who are ready to receive it. And I know just when and where to leave it..."
Tying it all together in the Epilogue would have the Fifth Doctor discover that device somewhere on a dinosaur dig site sometime in the early 1980s. Despite his best efforts to uncover its secrets, he is unable to see anything more than the very first adventure where Littlefoot meets his friends and they journey together to find the Great Valley. He eventually realizes that the key to unlocking all the data within the device is not to observe it privately but to share it with the universe piece by piece. He ultimately decides to hand over the device to the one person he believes would be best qualified to share such a remarkable series of prehistoric adventures: Don Bluth.
So, yeah, that's pretty much it. I'm unfortunately way too busy with other things to even consider trying to write this idea out into a complete story. If anyone is interested in taking this idea and turning it into a complete fanfic yourself, then by all means go right ahead and please let me know when I can read the whole thing.
