From the Super Mario Wiki
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After Mario and Luigi defeat Tolstar in Stardust Fields, they are soon rushed by three Beanbean knights at the entrance to Hoohoo Village. They accuse the brothers of kidnapping Prince Peasly, but Tolstar fortunately informs the knights that they are indeed the legendary Mario and Luigi of the Mushroom Kingdom. The knights apologize, and mention reports that the perpetrator wore an odd helmet and mumbled about "mustard and fink-rats", which turns out to be Fawful.