the most useful unofficial pokemon accessory ever made. in the early 2000s, nearly every pokemon player ran into the same problem. the internal battery in game boy and game boy color cartridges would slowly die, erasing your save file for good. these cartridges typically relied on cr2025 or cr2032 batteries that lasted roughly 3 to 10 years, depending on playtime and storage conditions. by the mid 2000s, millions of saves from the late 90s were at risk. one small device offered a lifeline: the monster brain. it resembled an oversized cartridge and usually cost just $10 to $15. you plugged your game into it to back up your entire save before swapping out the dead battery, then restored everything exactly as it was once the new one was in. it offered more than backups, though. the monster brain also let you edit almost anything, from pokemon stats and trainer names to rare items and a completed pokedex. in effect, it was a plug and play blend of gameshark cheats and a memory card.