>Terapagos appears, calls forth a being that shouldn't exist in this world (Sada/Turo)
>they refer to themselves as someone from the past of a world that may not even be related to yours
>explain how they are working on the dreamy idea of a machine that brings creatures from other worlds' pasts/futures into your own present
>motivated by a book full of fantasy stuff they read as children, they ask for your own book, which will "fuel their imagination" even more than before
>meeting ends and you wake up in your bed... except you still possess an item you obtained in the dream, a document that shouldn't exist in your world's present
>"All dreams are but another reality. Never forget."
No doubt Terapagos brings things from your dreams to you, and said dreams are reality in parallel worlds. So basically, both sides of this discussion won/lost? Paradox pokemon didn't/won't exist in our world, but since everything you imagine is real in the infinite multiverse the professor brings them to Paldea's present with its time machine.