The Action Replay is a device which connects to the side expansion port of the A500/+ (maybe compatible with the A1000). The device allows the user to freeze the computer at any point they choose where upon a new display opens and allows the user to view the memory contents, rip music and graphics or cheat in games. It also had the option of saving the memory to a bootable floppy disk which when loaded would place the memory in the exact state when the machine was frozen. This allowed the user to copy games by bypassing the copy protection and so forth. The device could also be used to slow the Amiga down which could also act as an aid in cheating in games.
Thanks to Iggy Drougge