The Music Changer is a level object that can change the stage music within a level on some conditions.
When clicked, it will allow the player to choose the music, and the trigger. The music can be selected from the stages in the same way music is set for the level. The three trigger options are: screen transition, vertical line or horizontal line. Screen transition is to switch the music after traversing the disconnected screen where the music changer is.
- According to Luigi, the music changer was planned to be added alongside the boss overhaul in 1.5.0 as the two features were similar thematically but was put aside due to the scope of the update.
- On the live stream for 1.7.0 where the development team answered questions from the community, in response to a question asking if there were any unintended features that the development team decided to keep in for 1.7.0, WreckingPrograms mentioned that there exists an exploit to change the music during a boss fight to stage level music but did not go into details—the feature was kept in for "advanced users".