Peach Beam
The Peach Beam is the upgraded version of the Star Beam featured in Paper Mario. This was the only ability that could nullify the power of the Star Rod when enhanced by Bowser and Kammy Koopa's special battle arena.
During the final battle, Mario attempted to use the Star Beam on Bowser in order to cancel out the power of the enhanced Star Rod, but due to Kammy's specially designed arena, the combined essences of the Star Spirits alone were unable to counteract Bowser's Star Rod misuse. After this unsuccessful attempt, Princess Peach, with some timely advice from the Star Kid Twink, made a wish to grant more power to the Star Spirits. The power of Peach's wish was so strong the Star Beam was upgraded into the Peach Beam, which had the ability to temporarily stop the Star Rod's power, but it isn't able to fully penetrate the effects of the Power Platform. When the Peach Beam was used during the battle, Twink would add his power to that of the Star Spirits, along with the power of Peach's wish and the hopes of the entire Mushroom Kingdom.
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Trivia
Although the Peach Beam was never seen in the Mario & Luigi series, once in Mario & Luigi: Bowser's Inside Story and Mario & Luigi: Dream Team, Peach and Starlow were seen using their combined powers to stop Bowser.