Mario Superstar Baseball
Bowser Monsters is the only unlockable team in Mario Superstar Baseball. They are also sometimes called the Bowser Flames, Bowser Blue Shells, and the Bowser Blackstars. Despite being unlockable, Bowser and Bowser Jr. can be chosen in Exhibition Mode before unlocking the team, but the Bowser Monsters team is not playable from the start in Challenge Mode. They are unlocked by beating Challenge Mode as any team on Special Difficulty. The team is also the Final Boss when playing as all the other teams in Challenge Mode. Bowser Monsters always practice at Bowser's Castle. The Bowser Monsters team plays a bit differently. Whereas all the other teams were trying to play a game against Bowser, when playing as the Bowser Monsters, Bowser heads out to challenge them. This is not necessary for Bowser, as he just sent out the letter but, of course, Bowser does not listen to Lakitu, and heads out to challenge them. After beating all the five teams, Mario and eight of the other Captains steal Bowser's Castle, and Bowser and his team must beat them to get them out.
Bowser's team is somewhat spread-out. He has four Dry Bones, and two variations of the Hammer Bro on his team, the Fire Bro and the Boomerang Bro. So, theoretically, Bowser has six different players, if the Fire Bro and Boomerang Bro are considered different characters from the Hammer Bro. Nonetheless, Hammer Bro, and its two alternate variations, is the unlockable character of the team, unlocked by beating Challenge Mode once as the Bowser Monsters.
Mario Super Sluggers
Unlike in the first game, Bowser's team in Mario Super Sluggers is only known as Bowser Monsters. The roster is similar, however Magikoopas are also available as extras now. Like with the predecessor, all the members of the Bowser Monsters have good chemistry with Bowser, with the Magikoopas and Hammer Bros. having good chemistry with Bowser Jr. as well.
The Bowser Monsters is tied with the Yoshi Eggs for having the most players on one team.