It wasn't bad, but I wouldn't really say it was that good :/ It was written like it took place in the anime world, but used the game mechanics for Pokemon and battles and such, and that kinda annoyed me through the entire creepypasta. There were also a few things, which... didn't really make sense. An example being this:
Crystal decided, digging into the memories of all the pokémon books she had ever read, that this pokémon had been bred, and for some reason sent to Johto. But something struck her – they couldn’t breed over in Kanto. Breeding was something new that had been introduced in her generation
I don't see how Kanto can be an entire generation behind, unless you somehow travel back in time, everytime you cross the border to Kanto, and that still wouldn't explain why that'd mean they wouldn't be able to breed Pokemon xD This combined with the game mechanics, like how they aren't able to see when attacks miss, aside from the fact that they didn't damage the opponent, kinda made some parts a bit annoying to read. It was also super easy to predict what would happen, once she'd encountered the Ghost Pokemon, which is one thing I also don't like that much about creepypastas. It's more entertaining if its a surprise, which is why I'd enjoy a poorly written creepypasta with elements of surprise, rather than a predictable creepypasta.
But all in all, it wasn't a bad creepypasta, I've just seen better :p