LBT and Pokemon:
As it turns out, the "World on the Reverse Side of Ours" mentioned in the Dex entry of the legendary Giratina refers to not only the afterlife, but every past, present, future, alternate world, fandom, and timeline of all media things ever created. We human beings didn't create any of our movies or write any of our books, we didn't make our manga and certainly never thought up our myths and stories. Those already existed, always have. Through some yet-to-be-deciphered mean and on some pandimensional level, everything pulses with what can only be described as 'echos', 'waves' of sporadic information, as if you gave someone a small corner of a photograph and told them to describe what is happening in the complete picture. Over time, someone may get enough waves to get a general idea of what the world the waves came from is like (or, as is more likely, a mishmash of waves from multiple worlds they have to connect together), and it usually comes in the spark of inspiration with a flurry of ideas, but since people think it is their creativity and their own mind that came up with this they copyright their idea as their own.
Now, if you keep all that in mind, let's say one day Giratina took a trip to the World on the Reverse Side of Ours, and it happened to take place in the Land Before Time fandom. Obviously, a 14'09" 1,654 pound winged six-legged centipede-dragon is bound to attract attention. From there, I will leave the reader to figure out one of the things that could happen, because I think I used up all my energy just writing out that first block of text and trying to see if it made any coherent sense.