Waldo the Wizard
From the Super Mario Wiki
Waldo the Wizard, also known simply as Waldo, is a wizard who lives in his own castle, which is presumably located either in or near the Mushroom Kingdom. Waldo speaks with a British accent, and as such, uses terms such as "jolly" and "cad." He is also shown to be rather skilled, as he can cast spells or create potions just by merely waving his hands around, and is also capable of flying.
At some point, King Koopa discovers Waldo's castle, and succeeds in banishing him from it. Assuming it actually belongs to King Koopa, Mario, Luigi, Princess Toadstool and Toad attempt to foil King Koopa there, but are captured and imprisoned in the dungeon by Mouser. It is there that Waldo reveals himself, by pouring his Magic Shrink Potion onto Mouser and two Koopa Troopas, shrinking them.
Waldo then introduces himself to Mario's group, and while using his magic to free them from their shackles, explains his situation to them and declares that he will reclaim his castle from King Koopa using his magic. This excites Toad, who grabs his Magic Shrink Potion in hope that he can use it on King Koopa. Joining Mario's group, Waldo follows them out of the dungeon, where Toad comes close to using the potion on King Koopa, but instead hits Mario and Luigi with it, shrinking them instead. Before Waldo can react, King Koopa lassoes himself, Princess Toadstool and Toad with a sausage rope. As Waldo cannot move his arms at this point, he is unable to cast a spell that can aid them.
Waldo, Princess Toadstool and Toad soon find themselves each tied to a lounge chair with rope, and can do little more than watch as King Koopa and the Koopa Troopa chase Mario and Luigi across the lawn of the courtyard. After Mario and Luigi run into the greenhouse, Princess Toadstool discovers that she, Waldo and Toad can move around if they shake themselves, as the chairs have wheels. By shaking themselves, they gain enough momentum to crash into the Koopa Troopas, breaking the chairs in the process.
Able to use his magic again, Waldo conjures up a Magic Growing Potion which Toad slips inside the spray gun that King Koopa is using to spray pesticide at Mario and Luigi with. When King Koopa sprays Mario and Luigi with the wrong potion, they not only returne to their normal sizes, but the vegetables surrounding them grow as well.
After Mario and Luigi use the vegetables to scare King Koopa and the Koopa Troopas out of Waldo's castle, Waldo conjures up a large, winged boot which proceeds to chase after King Koopa and repeatedly kicks him as he runs for his life. With the Koopa Pack no longer a threat, Waldo is once again able to live peacefully in his castle.