You have to save your game and then turn you console off. Then turn your console back on and set up your Pokemon game. Before you start your game under 'New Game' its says mystery gift. You can only use the mystery gift if you have a connection cable for your gameboy.
Chat with our AI personalities
The Mystery Gift in Pokemon Ruby, Sapphire, Emerald, FireRed, and LeafGreen all use the wireless adapter that goes into the GameBoy Advance to obtain special Nintendo events and/or DLC. (Downloadable content) The link cable was only used for the Mystery Gift in Pokemon Silver, Gold, and Crystal.
"LINK TOGETHER WITH ALL" and you will get the mystery gift. The mystery gift is used to get special event items when Nintendo gives them out.
Unlike the former Pokemon games Mystery Gift is used for NoA Events only. NoA Event = Nintendo of America Event This is currently the only known reason for Mystery Gift.
You can only get a Mareep by using a Wonder Card which is used in Mystery Gift and with the Wireless Adapter that alters the Pokemon inside Altering Cave allowing you to catch a Mareep, Teddiursa, Houndour, Stantler, Pineco, and Zubat (Which is the only Pokemon you can catch without Mystery Gift.).
Used on porygon to evolve to porygon2