From the Super Mario Wiki
A Fudjie is a chocolate bar that is available on Mushroom World. Mario is known to keep them in his pockets, so it is likely he is quite fond of them. In the episode "Up, Up, and a Koopa" in The Adventures of Super Mario Bros. 3 television series, Mario and Luigi are held captive in a cage on King Koopa's Doomship. Mario attempts to bribe their Rocky Wrench guard with a Fudjie, but the Rocky Wrench simply growls at him in disgust. A discomforted Mario then puts the Fudjie back into his pocket.