Changing Natures

[Weter 23]

I was playing Insurgence when I stumbled upon an area that changes your Pokémon's nature to a random one. I'm wondering how they managed to do that.

So, just something that allows a Pokémon's nature to be changed to something random, or specific. Perhaps even with certain items.

 

[Aki]

Check out the wiki article on Editing a Pokemon! You can easilly change the nature of a specified pokemon with a script call like poke.setNature(:HASTY) so the tricky part would probably be the specifics of how you want the palyer to be able to do this, and how you're going to regulate it.
If you want to make it random, I'd just roll a variable and have each result corelate with a specific nature. If you want the player to have to pay with some kind of item, I'd look into the move reminder who uses Heart Scales.