Mystery Datas are objects in the Net that contains random things such as Battle Chips, BugFrags, or Zenny. In some cases, viruses are hiding in Green Mystery Data, though this can be prevented with the SubChip "UnTrap".
- Green Mystery Data:
The most common Mystery Data. Can be found in the Net, random computers, or enemy computers. Every time MegaMan jacks out, they reappear. Contains small amounts of Zenny, a Battlechip, or a small amount of BugFrags. The contents of the GMD are based on the location of the player. For example, GMD in CentralArea1 will never give 1000 Zenny, but one in the Undernet might.
From BN4 onwards, Green Mystery Data can appear in battle. If the player finishes the battle with the GMD intact, they will get a reward in addition to their battle results. Both the player and enemies can destroy the Mystery Data.
- Blue Mystery Data:
Can be found in various computers and levels. BMDs are located in a preset location and cannot be aquired again once the player gets the BMD the first time. Contents can be HP Memory, Rare Battlechips, ExpMem, or even Navi Customizer programs. In some levels, they contain items required to progress, such as keys.
- Purple Mystery Data:
Found in various Net Areas, requires the SubChip "Unlocker" to open. Its contents are much greater than Blue Mystery Data, resulting in rather rare Battle Chips and powerful NaviCust parts.
- Gold Mystery Data: (BN6 Only)
The rarest of all of Mystery Data, and appears randomly. It replaces a GMD, and has extremely high rewards, such as copious amounts of Zenny, or even rare Mega Chips like NeoVari.