Theory: Perry and Vibe Island power up Peach

Abstract
Perry and the Crystals found on Vibe Island power up Princess Peach’s magical abilities during Super Princess Peach, which is why her magical abilities are more powerful for the duration of that title.

Arguments

 * Argument 1: In Super Princess Peach, Princess Peach uses magical abilities far beyond what she can do under normal circumstances. While Peach can typically levitate herself and other small objects for short periods and heal herself and others with her magic, in Super Princess Peach she can fly for extended periods of time and continuously heal herself. She is able to produce mass amounts of water from her tears and surround herself with flames.


 * Argument 2: In Super Princess Peach’s manual, Perry is described as a “magical umbrella” with “strange powers”. Through his dreams it’s revealed that he used to be an “oddly shaped boy” living on a mountain in a far-off land who had “strange powers”. An evil duo attempted to kidnap him for their boss, who wanted to use the boy’s “odd powers” to make the world his. The evil duo turned Perry into a parasol in order to transport him to their boss, but Perry wriggled out of their grasp and escaped. Perry’s powers later caused him to glow and get picked up by a merchant and later bought by Toadsworth once he felt the power emanating from him at the merchants’ store.


 * Argument 3: In Super Princess Peach, the Vibe Gauge has be filled in order for Peach to use her Vibe powers. The only ways the Vibe Gauge can be filled are when Peach collects Crystals or Perry “absorbs” enemies. The fact that Perry has to absorb enemies may indicate that Perry is the source of the Vibe Gauge or at least that Perry allows Peach to fill up her magical powers beyond her normal capabilities.


 * Argument 4: The Endless Vibe item is a drink which causes the Vibe Gauge to not run out. It features an image of a Power Star on the cup. This indicates that Star Power in the drink may be what allows Peach to use the Vibe Powers for such a long period, which is in line with Peach’s magic becoming more powerful with Star Power in games like Mario & Luigi: Bowser’s Inside Story.