Ok, this isn't gonna involve Princesses or anything, or forced marriages (unless you want the latter to come into play.) but it will involve transformations and magic.
For those who haven't seen Brave, basically there is this Princes Merida who is the daughter of a Scottish clan leader. She is expected to marry at 16 or something.
She is told by her mother of some tale where a kingdom was brought to ruin by a greedy prince who didn't want to share power with his brothers but wanted to be king. It's a "don't defy tradition tale".
She doesn't want to go through with picking a suitor and defies tradition. Her mother is hard on her and she attacks the family tapestry and then runs off. She follows will of wisps and finds a witch. She asks her for something to change her mom. The witch gives it to her.
She goes and gives it to her mom and it turns her into a bear. Merida didn't realize that. She is able to sneak her mother out of the castle with her triplet brothers helping her.
She goes to the witch's cottage and finds that she has to "mend the bond torn by pride" and has two or three days to do it before the spell becomes permanent.
Her mother learns to catch fish and stuff and they start getting along better. However, the spell starts to get more powerful. Her mother almost attacks her before regaining her right mind.
They later are led by wisps to the ruined kingdom and find that an enemy of theirs, the demon bear Mordu, is in fact the prince from the tale and had made himself a bear because he wished for the strength of 10 men, killed his brothers, and ended up, due to his pride, stuck as a bear permanently.
Eventually Merida figures out what to do, i.e. sew the tapestry, but in the meantime, the residents of the castle come and chase the mother, who appears to them to be an evil bear who the king guy thinks killed his wife or something.
Eventually, she is able to hold them off from getting the mother, but then Mordu comes and the mother and Mordu fight and Mordu is killed by a falling rock and his spirit set free. Merida fears that her mother won't turn back, as putting on the tapestry didn't work, and she is sad. However, at the dawn, it does work and her mother is restored to normal.
After that, Merida, who ends up getting her mother to change the rules so she only has to marry whom she chooses, ends up bonding with her mother.
Anyway, I was gonna do something for this Role Play kinda similar.
It would involve a formerly Leaf Eater villain, who, greedily want to rule the herd, found either a Rainbow Face and got a wish or found a Stone of Cold Fire and wished for superstrength and whatnot. He got turned into a Spinosaurus (the biggest of the Sharpteeth).
He then killed his rivals, but, as his herd now saw him as dangerous, attacked him, forcing him to kill them too. He was then eventually stuck as a Sharptooth for all time and didn't bother to break the spell. His home valley falls into ruin and is like a graveyard.
Meanwhile, in the Great Valley, one the characters, we can decide on whom, will get fed up with a parental figure (we can decide on that) and go find the Rainbow Face or the Stone of Cold Fire and get some special Tree Star or whatnot that will "change" the parent.
Upon eating the Tree Star, the parent is changed into a Sharptooth (perhaps a Spinosaurus, though we can decide) and the character has to get their parent outta the Great Valley so they don't get killed by the Combined Herd.
The character would then go searching for a way to reverse things, with the spell or whatever becoming more powerful as time passes and the parent becoming more naturally carnivorous and dangerous.
At the end, there would be a fight between the parent and the Spinosuarus guy.
It will be similar to Brave in ways, but can be adopted to fit Land Before Time. Other characters can be added too to help the central character. (Also, it could be Littlefoot and one of his grandparents that does this or Cera and Tria. It need not be a direct father or mother.)
As for roles, other than the Spinosaurus guy, I'm not sure. We should pick Littlefoot, Cera, Ducky, Petrie, Spike, or Ruby (having Chomper change his parents into Sharpteeth doesn't make sense!!!!) . Note, if we pick Ducky or Spike, perhaps they could both go off for the changing, as, for all practical purposes, they share the same parents.
We can also add other villains besides Spinosaurus guy, but Spinosaurus guy has to be the main bad guy.
Places:
The Great Valley
The Mysterious Beyond
Ruin Valley (where the bad guy lives)
