Professor Elvin Gadd (エルビン・ガッド博士), known more commonly as E. Gadd, is an inventor and scientific friend of Luigi and Mario. Luigi's Mansion for the Nintendo GameCube saw his first appearance, and ever since he has been a reoccurring character in the Mario series.
Despite his many appearances, E. Gadd has yet to make more than a small cameo in the Mario Kart series. Mario Kart DS almost featured him, but he eventually cut. Some of his inventions and a statue of him have made their way into the series.
Mario Kart DS Cancellation
Multiple sources confirm that Elvin Gadd would've been a playable racer in Mario Kart DS, but he was eventually scrapped and replaced by Dry Bones (so he likely would've been unlockable.) No model of E. Gadd or voice exists in the game... he used Toad's graphics and voice. Mario's game portrait and Kart were also used for the beta character.
- Mario Kart Arcade GP: A statue of the professor can be seen in Diamond City. Logos of his company, Gadd Science, and his face can be seen on a few other buildings, too.
- Mario Kart Arcade GP 2: His cameos reappear in Diamond City again.
- The Poltergust 4000 vehicle is based on one of Elvin's inventions, the Poltergust 3000.
- The professor's name, when shortened to "E. Gadd", references the word "egad", a word of surprise/excitement.
- There's a considerable amount of fans of the series advocating for E. Gadd to become a character.
- In Japan, his name is オヤ・マー博士 (Oya Mā-hakase), meaning Professor Oh My.