Action replay is like a hacking system used in the game. They have action replays in pokemon too .............

It is a device made by the UK Company Datel. It is kind of like gameshark/Game Genie. It is a cartridge (in this case a CD), that alters the game in some way. To give yourself infinite lives, magic, unlock all characters, always have this item, moonjumping, infinite nitros/turbo (was big for MK DS)

It's the Infinite Item Modifier.
It's self-explanatory.

As the others stated, it's used for hacking and overall cheating. You may see some characters flying ahead of you and there's nothing that you can do about it. And by flying, I really do mean flying.

Hacks and cheat devices.

Action Replay unfortunately!!!

They only use action replay because they are unfair and rude. That's low.

i hate ar
ruins a game

AR isnt out yet D:<

The fun of online experience is over. There will be a lot more hackers in the future, so we better get use to it i guess