Action Replay

Action Replay (previously GameShark) is the brand name of a series of cheating devices created by Datel, primarily used for changing the behavior of video games. Currently, Action Replay is available for a number of consoles including the Nintendo 64 and Nintendo GameCube which feature games in the Super Smash Bros. series; a version for the Wii is currently in production as well.

Nintendo 64 version
The version of Action Replay for the Nintendo 64 is inserted into the console's cartridge port. This version of Action Replay can be used to hack several features in Super Smash Bros.

Nintendo GameCube version
The version of Action Replay for the Nintendo GameCube attaches to the console's memory card slot, which, along with a separate disc, enables the player to access a debug menu, among other things. This version of Action Replay can be used to hack several features in Super Smash Bros. Melee, including the Debug mode, unlocking characters, infinite jumps, strange attacks variations, moveswapping (known for being very glitchy), and "super" codes which make attacks very fast. It can also be used to play with unplayable characters or on unplayable stages.

Wii version
The version of Action Replay for the Wii is currently in development. However, an alternative made by non-Datel people named USB Gecko has been released to the public as of now. The hacking features used in this are similar to Action Replay's, but do take note that playing as some unplayable characters (like the bosses) or playing some unplayable stages like the ones in the Subspace Emissary boss levels will freeze the game. For those who do not want to pay $50 for the USB Gecko, there is an alternative where the only requirement is an SD Card and the Homebrew Channel named "Ocarina". The homebrew channel download has been proven illegal by nintendo. It also could possibly damage your computer, SD, or Wii. For those who want to take that risk it is recommended rather than pay $50 for the USB Gecko. Though the hack is illegal, some argue if the "download" is illegal. some say yes, some say no. The answer remains unknown.