Professor E. Gadd

"Ooof... I sure take a lot of knocks in this line of work. I'm getting too old for this ghost-catching tomfoolery. Anyway, nice to meet you. I'm Professor E. Gadd."

- Professor Elvin Gadd

Professor Elvin Gadd, often shortened to Professor E. Gadd or simply E. Gadd, is a scientist who debuted in Luigi's Mansion and the founder of Gadd Science, Incorporated. He always makes ambiguous gibberish sounds when speaking (supplied by Kazumi Totaka, who took inspiration from Animal Crossing's "Animalese" when inventing the voice ), and he frequently uses phrases such as "criminy," "hullabaloo," etc. His name comes from the archaic exclamation "egad," something that one says in surprise.

Background
In his past, E. Gadd lived on the foothills of the Thwomp Volcano, as depicted in Mario & Luigi: Partners in Time. The Mario Bros. go back in time and end up saving his lab from burning down when fire blocks erupted from the Thwomp Volcano. He then helps the Mario Bros. by inspiring his older present self to create the Hydrogush 4000; as the Mario Bros. are in the present, he starts to get the idea for the device, which transfers to his future self. The present-day Professor E. Gadd uses the Hydrogush 4000 to send water through via time hole and calm the erupting Thwomp Volcano. Afterwards, the twenty-year-old E. Gadd moves to Boo Woods, where he would later study ghosts. In order to get funding for his ghost research, E. Gadd also started a cafe franchise called Starbeans Cafe.

Luigi's Mansion
Many decades later, in Luigi's Mansion, Luigi enters the mansion and is saved from a Gold Ghost by Professor E. Gadd wielding the Poltergust 3000, as shown in a cutscene. The professor reveals that 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 the Poltergust 3000 and the Game Boy Horror. The professor continues to help Luigi throughout the game, giving him help and tips.

Luigi's Mansion: Dark Moon
After a few years of absence, Professor E. Gadd appears in Luigi's Mansion: Dark Moon. In the game, E. Gadd takes up residence in Evershade Valley after learning that the ghosts there are friendly. Eager to examine ghosts without fear of being attacked by them, he sets up a laboratory in the Gloomy Manor and a Bunker close by the mansion. There, he begins researching the ghosts of the five mansions that populate the valley, and sends his five Toad assistants to the other four mansions in the valley to examine the ghosts there. At first, the resident ghosts welcome him and assist him in his lab, but when King Boo arrives and destroys the ghost-pacifying Dark Moon that hangs over Evershade Valley, the ghosts start running amok and destroy E. Gadd's equipment. He flees to his nearby Bunker and enlists the help of Luigi &mdash; who has now taken up residence in his new Grade D mansion from the previous game &mdash; to help rebuild the Dark Moon and calm the ghosts once more. E. Gadd was later revealed to have been unintentionally and indirectly responsible for King Boo's return, as he had sold his portrait in a garage sale (a car boot sale in the British English version), thus ensuring his escape.

In this game, E. Gadd has made an upgrade of his Poltergust 3000 from the last game: the Poltergust 5000. This new Poltergust uses a Strobulb to stun ghosts, rather than the flashlight used with the Poltergust 3000. Professor E. Gadd also introduces three new inventions: the Pixelator, a machine that turns Luigi into pixels and transports him to and from the different mansions, the Dual Scream, a device that resembles a Nintendo DS and is capable of communication, and the Dark-Light Device, which allows Luigi to see invisible objects. He doesn't leave the Bunker until the end of the game, directly after beating King Boo.

Luigi's Mansion Arcade
E. Gadd has a similar role in Luigi's Mansion Arcade to that of Luigi's Mansion: Dark Moon, in that he communicates with Luigi while the latter explores the mansions, and offers a tutorial to the player upon starting the game.

Luigi's Mansion 3
E. Gadd returns in Luigi's Mansion 3. Having been tricked by Hellen Gravely into coming to the The Last Resort, E. Gadd is trapped in a painting and his ghost collection, including King Boo, is released. He is later saved by Luigi, who escaped a similar trap and borrowed the Poltergust G-00 from E. Gadd's car in the hotel's basement. E. Gadd initially attempts to flee the hotel, but when Luigi insists on staying to save his captured friends, E. Gadd relents. After setting up his portable lab in the basement, E. Gadd gives Luigi the Virtual Boo for communication purposes. He later has Gooigi accompany Luigi throughout the hotel. He also uses the lab to provide a safe haven for the saved Toads.

Towards the end of the game, King Boo attacks Professor E. Gadd's lab when Luigi follows after the recently-released Mario to find Princess Peach, and traps him and everyone else in a single painting. Luigi was saved from this by Polterpup, and he manages to recapture King Boo and free all his friends. He also offers to help the ghosts rebuild the then-recently destroyed Last Resort complex, providing construction hard-hats to Luigi and some of the ghosts (although a Hammer obliviously eats his). After the hotel is rebuilt in E. Gadd's likeness, Professor E. Gadd stays behind with Gooigi and the ghosts while everyone else departs.

Super Mario Sunshine
Although Professor E. Gadd does not appear in Super Mario Sunshine, when Mario initially finds F.L.U.D.D. at the Delfino Airstrip, it says, "Thank you for purchasing this item from Gadd Science, Inc." Later, Bowser Jr. says he got his Magic Paintbrush from "a strange old man in a white coat." Bowser Jr. uses the paintbrush to frame Mario and get him away long enough for himself to go in and kidnap Princess Peach. This is a fitting description of Professor E. Gadd, which is further confirmed when F.L.U.D.D. seems to react in surprise to the statement. Bowser Jr. claims E. Gadd gave the brush to him of his own free will and that he did not know the professor's name when he received the brush, but it is unknown whether this is true or not. There is a symbol on both the Magic Paintbrush and F.L.U.D.D. showing a face and hairstyle similar to E. Gadd's, which seems to be the Gadd Science, Inc., logo. It appears on many of E. Gadd's other inventions, as well as the boxes for F.L.U.D.D.'s nozzle upgrades.

Super Mario Maker
E. Gadd makes an appearance in Super Mario Maker as a Mystery Mushroom costume for Mario when using the Super Mario Bros. theme. The costume can be unlocked by completing the Event Course Paranormal Research.

Mario & Luigi: Superstar Saga / Mario & Luigi: Superstar Saga + Bowser's Minions
In Mario & Luigi: Superstar Saga, the professor makes an appearance supplying the brothers with an array of accessories to help them along their way each time they drink at Starbeans Cafe, a juice shop that he owns. However, it has been found that originally, the game was only going to feature Professor E. Gadd once, the first time Mario and Luigi get a drink (with cut dialogue indicating he was originally supposed to be specifically given the Woohoo Blend); in all of the future times, different characters would have appeared. These characters are Wario, Samus Aran, Fox McCloud, Link, an Excitebike racer, and Captain Olimar.

While Professor E. Gadd reprises his role as the Starbeans Cafe owner in the remake of Mario & Luigi: Superstar Saga, Mario & Luigi: Superstar Saga + Bowser's Minions, he also shows up during the Minion Quest: The Search for Bowser side story. Here, he is found in a cave by Bowser's minions, claiming to have followed ghosts when he fell in. E. Gadd begins talking to Bowser's minions about his research, and says he is also working on a time-travel device, a nod to the original main story's sequel. He also alludes to the Starbeans Cafe and reveals he founded the company as a way to get funding into his ghost research.

The professor has many different reactions for each time a new drink is made at Starbeans Cafe, usually accompanied with a humorous scene.
 * Reactions to the drinks
 * The first reaction gives a reference to Luigi's Mansion when the new brew attracts a Ghost from the game, which scares Luigi, but the professor comes in with the Poltergust 3000, and sucks it up. The professor explains that he owns the Cafe, and that each time he samples a new brew, he will give a gift to the Bros. He samples the brew and gifts to them the Greed Wallet.
 * The second reaction has the professor drawn in by the smell of the drink, and samples a flavor. He then gives the Bros. the Bonus Ring. The professor then has a major reaction to the very "Strong Brew" and asks the bartender where the bathroom is. The Bartender replies that he had never built one. Luigi then rushes to get the Poltergust 3000 and sucks the professor in.
 * The third reaction has him on a Poltergust 3001, a rocket. He samples the drink and gives the Excite Spring before blasting away.
 * The fourth has him on a giant Game Boy Horror. He sends a ghost as a representative for the sampling, much to Luigi's terror. After that, the ghost drops the Great Force.
 * In the fifth reaction, he has the giant Game Boy Horror send the drink to him. He then gifts them the Power Grip in the original or Secret Specs in the remake. He promises to come in person.
 * In the sixth reaction, E. Gadd comes wearing a suit that makes him a ghost. He samples the drink and gives the Cobalt Necktie. A terrified Luigi uses the Poltergust 3000 to suck the professor inside.
 * In the final one, he samples the last drink and proclaims it the best one, much to his employee's annoyance. He gives the Bros. the Game Boy Horror SP. Before leaving, he hangs a photo of himself in the shop as a way to brighten one's spirits, which the employee labels dumb.

Mario & Luigi: Partners in Time
E. Gadd has a much larger role in Mario & Luigi: Partners in Time, where the professor debuts his newest invention to the Mushroom Kingdom, a time machine in Peach's Castle. Princess Peach, accompanied by Toadiko and Toadbert, volunteers to be a passenger on its maiden voyage. However, when the time machine returns, it is not the trio that left but rather the Junior Shrooboid that emerges instead. After the bros. defeat it, Gadd places the creature inside a tube of fluid, keeping it alive and allowing him to study it. Out in the courtyard, Mario and Luigi discover a hole in the ground; E. Gadd elaborates that this hole is a time hole, a rip in the time-space continuum, which was created by the use of the time machine. After Luigi falls in the hole and Mario heads in to save him, the professor sends Stuffwell, a sentient suitcase, through to help them. For most of the game, E. Gadd is seen studying the Junior Shrooboid defeated earlier. He is able to communicate with Stuffwell even if the brothers and Stuffwell travel to the past. At Thwomp Volcano, Mario, Luigi, and their baby counterparts come across and paradoxically meet a younger Professor Gadd, who is studying Thwomps. During this time, though, the volcano erupts, with several Thwomps falling in and destroying the laboratory. One threatens to explode, and must be put out; Baby Mario and Baby Luigi do this by having Baby Mario drink water and Baby Luigi hammering him to spit it at the Thwomp, dousing it. Witnessing this event in the past causes the present day E. Gadd's memories to be rearranged and inspires him to invent the Hydrogush 4000, a massive water pump. Mario and Luigi then have him pump water through the time hole leading to Thwomp Volcano to douse the mountain. After his lab is destroyed by the eruption of the volcano, young E. Gadd mentions his interests in studying ghosts, and that he would be buying a lab at the edge of Boo Woods, nodding toward his first appearance in Luigi's Mansion.

After discovering that baby tears are the Shroob's weakness, Mario, Luigi, and Princess Peach relate this to the professor. E. Gadd then uses the Hydrogush to pump a liquid similar to Baby Luigi's tears through the time holes, removing the Shroobs and restoring any Shroobified characters. He also restores the time machine and uses it to bring everyone back to the future.

Mario Party series
A flashlight known as the Gaddlight was used to scare away Boos when they try to steal a Star or coins in Mario Party 4.

In Mario Party 5's Super Duel mode, several vehicle parts are designed by E. Gadd.

Professor E. Gadd's garage is a game board in Mario Party 6. When a player lands on a ? space on this board, E. Gadd appears and lets them try one of his inventions.

In Mario Party Advance, E. Gadd appears as the co-host of Play Land. The coins earned in the minigames can be used to buy Professor E. Gadd's many "Gaddgets".

A magic wand bearing Gadd's logo later appears in Mario Party 7.

Mario Kart series
E. Gadd's inventions are sometimes used as items in the Mario Kart series, along with Robo Mario from the arcade games.

Mario Kart DS
In Mario Kart DS, the Poltergust 4000 kart used by Luigi is based off of E. Gadd's Poltergust 3000 invention. There is evidence in the US demo prototype version he was going to be playable which would have been his first playable appearance, being replaced by Dry Bones in the final version.

Mario Kart Arcade GP series
E. Gadd makes a small cameo in Mario Kart Arcade GP as a statue in the background of the Diamond City course in the Wario Cup. His face, the logo of Gadd Science, appears on a building as well. This cameo carries over into the sequel, Mario Kart Arcade GP 2.

It is implied that E. Gadd is the creator of Robo Mario, as evidenced by the logo on Robo Mario's cap.

Super Smash Bros. series
E. Gadd makes a small cameo appearance in Super Smash Bros. for Nintendo 3DS as a collectible trophy. The description of his trophy talks about his role within Luigi's Mansion: Dark Moon, describing the events of the Dark Moon being shattered, and the professor calling upon Luigi to aid him. E. Gadd is referred to by his full name - Professor Elvin Gadd - in American English, while the British English version has his first name abbreviated.

Additionally, E. Gadd appears as a spirit in Super Smash Bros. Ultimate, as well as "EGADD" being one of the randomly generated names the player can receive.

Despite not appearing in any Super Smash Bros. titles until the fourth installment, E. Gadd is mentioned in the Vacuum Luigi trophy in Super Smash Bros. Melee, the trophies for F.L.U.D.D. and the Poltergust 3000 in Super Smash Bros. Brawl, the trophy representing the various Ghosts that appeared in Dark Moon in Super Smash Bros. for Nintendo 3DS, and Luigi's Final Smash trophy, the Poltergust 5000, in Super Smash Bros. for Wii U.

Inventions
A device created by E. Gadd with the aid of the Mario Bros. which is designed to contain captured Boos. It is stored in the Bunker's Vault.
 * Boo Canister

A handheld device that bears a striking resemblance to a Nintendo DS used briefly by E. Gadd to find Princess Peach in Mario & Luigi: Partners in Time. It has the ability to pinpoint which time period someone is trapped in. One of the Toads thinks he just made it up. Also, when Professor E. Gadd turns on his Hydrogush 4000, he uses a DS-like device.
 * DS time radar

An upgraded DS given to Luigi in Luigi's Mansion: Dark Moon, that acts both as a communication device, and as a map of the area.
 * Dual Scream

Special parts that can be bought in the Super Duel Mode of Mario Party 5. They include the E. Gadd body, E. Gadd Jet, E. Gadd Engine and E. Gadd gun.
 * E. Gadd Battle Machine

E. Gadd's garage is the garage he had in Mario Party 6. He also keeps his numerous inventions there. It also appears as a Rare Mini-Game.
 * E. Gadd's Garage

Electronic portals in Luigi's Mansion: Dark Moon that can be used to transport people and things from one place to another. Comes in a pair, but only one of them has a panel on the top that must be turned on with a Strobulb flash for both to be activated.
 * E-Gate

The Flash Liquidizer Ultra Dousing Device, better known as F.L.U.D.D., is a water-spraying device used by Mario in Super Mario Sunshine. It is worn on Mario's back, and has various nozzle attachments which can be collected by breaking open boxes with E. Gadd's logo on the front. F.L.U.D.D. also has notable artificial intelligence and the ability to communicate with a voice.
 * F.L.U.D.D.

The Gaddgets appear in Mario Party Advance. There are 80 total, and are very similar to the toys in the WarioWare games.
 * Gaddgets

A flashlight that is used to scare away Boos when they try to steal a Star or coins in Mario Party 4.
 * Gaddlight

The Game Boy Horror is a portable device from Luigi's Mansion that bears a striking resemblance to the Game Boy Color containing a built-in camera which E. Gadd can use to watch the action from the safety of his lab and contact Luigi. It also stores data including a map and anything Luigi has collected, and contains a special radar called the Boo Radar to find hidden spherical objects.
 * Game Boy Horror

The Game Boy Horror SP is an upgraded version of the Game Boy Horror, given to Mario by E. Gadd in Mario & Luigi: Superstar Saga. It is another portable device, this time bearing a striking resemblance to a Game Boy Advance SP. It always gives the Bros. access to rare items in battle.
 * Game Boy Horror SP

A machine that holds the ghosts captured throughout Evershade Valley and the ScareScraper in Luigi's Mansion: Dark Moon. It also provides research information on all captured ghosts including their spectral mass (weight).
 * Ghost Container

A pale blue jacket that, when worn, turns characters into a ghost. When E. Gadd wore this in Mario & Luigi: Superstar Saga, Luigi got scared and used the Poltergust 3000 to vacuum him up.
 * Ghost Gown

The Ghost Portrificationizer is a large machine which works in conjunction with the Poltergust 3000. Certain ghosts captured can be entrapped in portraits to be hung in E. Gadd's gallery. The machine also works in reverse, which was utilized to free Mario from the painting he had been trapped in by King Boo. E. Gadd also commented that it took him twenty years to build.
 * Ghost Portrificationizer

Gooigi is the result of an accidental combination of ghost ectoplasma and coffee. With testing, Gooigi was able to take on the form of Luigi and was sent back in time to the events of Luigi's Mansion. Gooigi also accompanies Luigi in Luigi's Mansion 3.
 * Gooigi

A vault E. Gadd made to contain the ghosts of Evershade Valley and the ScareScraper in Luigi's Mansion: Dark Moon. It holds the Boo and Ghost Containers, a machine where Gemstones and their statues are stored, as well as a device which displays Poltergust 5000 upgrades, and a Bank Vault where treasure that is collected throughout the game is stored and tallied.
 * E. Gadd's Vault

A large water pump used in Mario & Luigi: Partners in Time. It's not portable like the F.L.U.D.D., but it does have enough power to extinguish the eruption of a volcano.
 * Hydrogush 4000

A magic wand in Mario Party 7, which has the E. Gadd logo on it. It is exclusive to Boo and Dry Bones. It was used to turn the characters invisible, making them impervious to traps, and to double their rolls on Dice Blocks for two turns.
 * Magic Orb

The Magic Paintbrush is used by Bowser Jr. (as Shadow Mario) in Super Mario Sunshine. It is a large paint brush with the ability to paint various colors, though this magic paint can change the landscape, create portals, and create obstacles or enemies. It is unclear why E. Gadd made the brush, as well as why it was given to Bowser Jr., though the latter may be due to Bowser Jr. being disguised as Mario. Throughout the Mario franchise, Bowser Jr. uses the Magic Paintbrush as his signature weapon.
 * Magic Paintbrush

A maze-making machine from the Mario Party 6 minigame Lab Brats.
 * Maze Manufactory

A device that allows E. Gadd to detect and measure distant paranormal signals and pieces of the Dark Moon from his Bunker in Luigi's Mansion: Dark Moon.
 * Parascope

E. Gadd uses the Pixelator to send Luigi, and his Toad assistants, from the various mansions in Luigi's Mansion: Dark Moon. The Poltergust 3000 is a modified vacuum cleaner designed to entrap ghosts. It also has a "blow" function which allows it to expel elements it sucks up such as fire, water, and ice. Luigi uses this in Luigi's Mansion to defend himself from the many ghosts; it also makes a return in Mario Power Tennis where Luigi uses it as his defensive Power Shot, using its suction power to retrieve the ball. It also appeared in a trophy in Super Smash Bros. Melee and Super Smash Bros. Brawl. The Poltergust 3000 is also used by Luigi in Mario Sports Mix for his special ability.
 * Pixelator
 * Poltergust 3000

The Super Poltergust 3001 is an advanced version of a Poltergust 3000. It has the same functions as the Poltergust 3000, but is much larger thereby allowing it to be ridden on. When ridden, it hovers over the ground. It is capable of moving at high speeds. E. Gadd briefly demonstrates the invention and uses it in Mario & Luigi: Superstar Saga.
 * Super Poltergust 3001

The Poltergust 4000 is one of the vehicles used by Luigi in Mario Kart DS to race in. It is similar to the Super Poltergust 3001, though it does not float. The "barrel" of the car is the area Luigi sits on, and the nozzle rests on the ground. Emblems are placed on both sides of the barrel.
 * Poltergust 4000

A vacuum that Professor E. Gadd creates for Luigi to vacuum up more ghosts in Luigi's Mansion: Dark Moon. It is a successor to the Poltergust 3000 and it creates a large circular sucking motion rather than the small sucking motion from the first game, making it a lot easier to defeat multiple ghosts at once. There are also different accessories designed for the Poltergust 5000, such as the Strobulb and the Dark-Light Device.
 * Poltergust 5000

The Poltergust G-00 is Luigi's Vacuum in Luigi's Mansion 3. This one retains the Strobulb and Dark-Light Device, can fire a toilet plunger to help pull certain objects, and can summon Gooigi.
 * Poltergust G-00

This robotic entity of Mario races against players in the Rainbow Cup challenge game in Mario Kart Arcade GP 2. It spawns an infinite number of items and changes items depending on its place.
 * Robo Mario

The beverage shop in the Beanbean Kingdom, founded and owned by E. Gadd. Every time Mario and Luigi mix a new drink, E. Gadd visits. This continues until E. Gadd stops visiting and puts up a larger-than-life-size portrait of himself.
 * Starbeans Cafe

An intelligent suitcase used by the Mario Bros. on their quest in Mario & Luigi: Partners in Time. Its purpose is to manage the brothers' inventory and display their current status. It also helps the brothers by activating the Shroob Saucers that are used in the game, and eventually near the end develops the ability to return to the past before rescuing Princess Peach. It is known to use large and overly complex made-up words when he speaks, and upon ending its speeches, says "BACK TO ADVENTURE!"
 * Stuffwell

Used by Princess Peach to visit the past at the beginning of Mario & Luigi: Partners in Time. It is powered by the Cobalt Star. It breaks at the beginning of the game but is repaired after the Shroobs are defeated, and due to the loss of the Cobalt Star, re-engineered to run off energy from the time holes.
 * Time Machine

A vacuum from Mario Party 7. It is a capsule item exclusive to Wario and Waluigi. It doesn't look much like the Poltergust 3000. Rather, it is yellow and purple (much like the two characters that use it), and features the E. Gadd logo. It is used to steal coins from other players.
 * Vacuum Orb

An item from Luigi's Mansion 3 that allows Luigi communicate with E. Gadd, check the map, and the pause screen. E Gadd also refers to it as the "VB".
 * Virtual Boo

Mario & Luigi: Partners in Time

 * Guide bio: "The Mushroom Kingdom's resident mad scientist, Professor E. Gadd, is responsible for creating the time machine. The professor will aid Mario and Luigi by offering advice and guiding the brothers to their next objective. He talks like an Ewok."

Website bios
"Known for his paranormal research and plethora of wild inventions, Professor E. Gadd just needs someone crazy enough to put them to the test." "An eccentric scientist who invented the Poltergust 5000, a big improvement on the previous 3000 model. After the ghosts turn hostile and take over mansions, he calls on his old friend Luigi to help out."

Luigi's Mansion 3

 * In-game bio: "A genius inventor and the leading authority in the field of ghost research. His beloved ghost collection is said to be the best in all the world! He supports Luigi in his adventures...from the safety of his Lab, that is!"

Trivia

 * In Super Smash Bros. Brawl, one of the names that can appear when a player presses the random button when naming their custom stage is "EGADD".
 * Glasses with swirls that are often seen in Japanese media are a feature E. Gadd shares with Professor Frankly, Fawful, Francis, and Iggy Koopa.
 * Occasionally, E. Gadd's voice-overs includes "Oyamaa", which is both his Japanese name and an exclamation of surprise. This happens even in overseas releases. He can also sometimes be heard saying "Luigi!" or "Mario!"
 * Professor E. Gadd is one of the few characters in the franchise who existed prior to Nintendo's translating games and websites to Dutch, Portuguese, and Russian to receive a new name in said translations, as opposed to keeping his English name.
 * If one views E. Gadd at a certain angle, it is shown that he has small dotted eyes.
 * In Luigi’s Mansion 3, one of the poses E. Gadd strikes if flashed by the Strobulb references Marilyn Monroe's famous "white dress scene" in . The back of his lab coat even flutters upward during the pose.
 * In The Legend of Zelda: The Wind Waker, there is a character named Mako whose face resembles E. Gadd's.