It's possible you are referring to a fan-made concept or a misunderstanding of existing Pokémon lore. Here's why:
* Dialga is a Legendary Pokémon: Dialga is known for its control over time and its ability to change the flow of history. It doesn't have a specific item associated with its "Primal" form.
* Primal Forms: The "Primal" form is a unique feature of certain Legendary Pokémon, usually triggered by a specific item or event. While Dialga has a "Primal" form in the games, it doesn't have a corresponding flute or item to activate it.
If you have any more information about where you came across this term, it would be helpful in understanding what you're referring to.