Phantasy Star Online
Every player is given a single MAG at an early level through a story quest, Magnitude of Metal. More may be found later in the game as rare drops. A MAG can be fed three items in a single feeding, after which you will not be able to feed it anything for 150 seconds (2.5 minutes). The diet will determine the stats of the MAG, as different items will raise or lower the progress of increasing different stats. A player may only equip a single MAG at a time, and the player's stats will be boosted according to the stats of the MAG equipped. It is important to note that unlike other equipment, the stats granted by a MAG are added to the player's base stats and can help to meet the use requirements of weapons and technique disks.
Much like Pokémon, MAGs will evolve and change names and physical forms at several level thresholds. Unlike Pokemon, all start with the same form (named simply "MAG") and the different forms it may take are determined by the current stats when it reaches an evolution level. There are many special evolutions (many of them Easter eggs referencing other Sega games) that can only be reached by carefully managing a MAG's diet to ensure that its stats exactly meet the evolution requirements.
After a MAG has reached its first evolution it will have access to its Photon Blast ability, which are powerful special abilities that will pause combat while a summoning animation plays. The ability is only available when the PB charge meter reaches 100, which charges slowly when the player deals damage to enemies and charges quickly when the player receives damage from enemies. Each subsequent evolution adds another available Photon Blast ability, for a total of three options on a fully evolved MAG.