Dreambeats

The Dreambeats are a type of music created by Antasma that make the hearer fall asleep randomly. Some such as Pi'illos, Starlow (possibly because she doesn't appear to have ears), and Antasma are unaffected by their tone.

In the story, once Mario, Luigi, Dreambert, Starlow, and the Massif Bros. reach the top of Mount Pajamaja, Bowser and Antasma are planning to blow the Dreambeats out of some speakers.

This easily knocks out Corporal Paraplonk, Sergeant Guy, and Private Goomp and Luigi almost faints from the music. Even Boss Brickle and Broque Monsieur could hear it all the way down in Mushrise Park and Pi'illo Castle!

Mario is forced to go into a nearby Dreampoint in order to wait the Dreambeats out. Unfortunately, the Dreambeats cause the Dream Portal to close, trapping Mario and Dreamy Luigi.