Musical notes are gimmicks that first appeared in the console/PC version of Sonic Generations. They are note-shaped objects used for different purposes.
Though their design slightly differs between games, the musical notes generally resemble eighth notes/quavers. Usually, if the player touches it, it will bestow specific items that depends on the game.
In the console/PC version of Sonic Generations, after clearing a Challenge Act and ringing the Bonus Bell on the Challenge Act Gate, a musical note appears and fly vividly around the area. Catching the musical note adds a new artwork or music tracks to the Collection Room. A blue musical note gives the player an artwork, while a yellow musical note gives the player a music track. As the musical note floats around, a countdown of twenty seconds is shown directly above the musical note. If the player cannot catch the musical note by then, it disappears and the player must start over.
The musical note also appears in the Challenge Act, Vector: Pick Up the Beat. Here, Vector produces a blue Musical Note and sends it at Sonic. The objective is to Homing Attack the musical note and knock it back at Vector thirty times in order to make him miss the beat of the music. The color of the Musical Note changes to yellow after ten hits and to red after twenty hits. Each time the musical note changes color, it becomes faster and harder to hit
When using the Magenta Rhythm in its appropriate place, the musical notes will appear in midair to show the player's path. If the player touches the musical note at the right time on the Wii U GamePad as the Magenta Rhythm, it disappears with a high note and awards the player with a Ring.