Hello, Manipulation. You're probably getting tired of ROM hacking questions by now, but I have one for you...
There's a "special" event called in Emerald near the beginning, when you select your Pokémon. Unfortunately, this event ALSO starts a battle with a wild Zigzagoon. I just want to change the Zigzagoon into another Pokémon. Trying to search for Zigzagoon's ID in Hex feels like trying to find a needle in a haystack, plus I'm unsure of how exactly it's stored for that event in the first place.
There was a tutorial on another site that covered it a long time ago, so I know it can be done... but they took it down, it isn't saved in the Internet Archive, and I haven't been able to find information on it anywhere else.