|Professor Elvin Gadd|
|Living Town||Luigi's Mansion|
|Main Weapon(s)||Poltergust 3000|
|First Appearance||Luigi's Mansion|
|Latest Appearance||Luigi's Mansion: Dark Moon|
Professor Elvin Gadd or Professor E. Gadd is the scientist first appearing in Luigi's Mansion, and founder of Gadd Science Incorporated. He always speaks in ambiguous gibberish.
Many decades later, in Luigi's Mansion, Luigi enters the mansion and is saved from ghosts by a strange old man wielding a vacuum cleaner. Professor E. Gadd reveals he lives in a house near the mansion, where he researches his favorite subject: ghosts. Luigi explains his brother Mario is missing within the house, and the professor decides to help Luigi by giving him two of his inventions, the Poltergust 3000 and the Game Boy Horror. The professor continues to help Luigi throughout the game, giving him help and tips.