Gameshark isn't anything that exists inside the game. It's a cheating engine for PlayStation, and it lets you do various things, such as putting Aeris in your party (SPOILER)after her death. When I do the (SPOILER)reviving Aeris cheat, I usually give Aeris Princess Guard, Mystile or Minerva Band, and Ribbon. I also give her Knights of the Round, and put her in the final battle against (SPOILER)Safer*Sephiroth, and have her defeat him with Knights of the Round. Payback time!