When it’s revealed that Dr. Eggman is not actually a doctor, he becomes a joke and must go back to school to finish his Ph.D. in evil.
- Admiral Doom (Mentioned)
- Beth the Shrew
- Captain Hero (Mentioned)
- Child Monkey
- DangerCo Deadly Equipment Warehouse Worker
- Dr. Eggman
- Fastidious Beaver
- Fennec Male
- Lady Goat
- Lady Walrus
- Lightning Bolt Society
- Male Fennec
- Mayor Fink
- Mike the Ox
- Mrs. Dave's Mom (Voice only)
- Mrs. Vandersnout
- Nominatus (Cameo)
- Old Monkey
- Pepper People (Cameo)
- Professor Kingsford (First appearance)
- Rabbit Girl
- Sheep Villager
- Soar the Eagle
- T.W. Barker
- Team Sonic
- Walrus Camera Man
- Walrus Male
- Warthog Male
- Wild Cat
- Sonic Boom World
- Amy's ride (First appearance)
- Blue Force One
- Hoverboard (x3)
- Knuckles' monster truck (First appearance)
- Sonic Speedster (First appearance)
- Tails' Plane (Cameo)
The episode begins with Dr. Eggman arriving at the DangerCo Deadly Equipment Warehouse with Orbot and Cubot to do some shopping. At the checkout however, the DangerCo Deadly Equipment Warehouse Worker wants to see Eggman's credentials, as only those with a doctorate in Evil Science are allowed to shop at the warehouse. Eggman elaborates that the last time he was at the warehouse, he "sweet-talked" with the clerk (by threatening the clerk's family) into letting him shop there. Aware of this since it was his family Eggman threatened last time, the Warehouse Worker reveals that he is no longer intimidated by his threats, as he has since been divorced and has nothing to lose. Having no choice, Eggman has Orbot print out his transcript. Upon reading it though, the Warehouse Worker sees that Eggman is two credits short of his graduation requirements, meaning he is not a legitimate doctor. Having enough of this conversation, Eggman leaves with Orbot and Cubot.
Nearby, Staci has overheard the reveal of Eggman's missing Ph.D. She promptly decides to spread the word in song, starting by calling her sister Perci on the phone. A musical number quickly ensues where the villagers (Team Sonic included) start gossiping between each other and sing about how they now see Eggman as a fraud and cast aside notion about him being a threat, all while giving him the new nickname "Mr. Eggman". The musical number ends with the villagers and Team Sonic having gathered at Meh Burger to do a dance routine, just as Eggman arrives at the restaurant. Resuming relative normality, the villagers chat between each other while Eggman tries ordering a double Meh Burger from Dave. Dave, however, responds with a sarcastic remark that makes the villagers laugh at Eggman. Feeling insulted, Eggman threatens to destroy them all, only for Tails and Sonic to verbally burn Eggman about having no Ph.D. further. Dave then asks Eggman to leave, and Salty takes it upon himself to forcefully throw a vengeful Eggman out of Meh Burger while the villagers laugh at Eggman. As Sonic and Knuckles resume their casual conversation however, Eggman returns with his Eggmobile to shoot everyone with its laser gun. Sonic takes out the laser gun however, and mocks Eggman further with his new nickname. With the villagers continuing to laugh at him, Eggman leaves in a foul mood.
Back in his lair, Eggman complains about his day to Orbot and Cubot until the former inspires him to go back to school and earn the final two credits for his graduation. Eggman also decides to take the class of Professor Kingsford, a feared professor in evil back on campus, who would always make one of his students his goat and wail mercilessly on him for the entire semester (earning him the nickname "the goat herder"). Eggman himself is excited to see who the "poor sap" is going to be this year. On his first day of school, however, Eggman oversleeps. As such, he is forced to awkwardly enter his class, which includes Dave, Charlie, Belinda, Willy Walrus, Dave and the Weasel Bandits, at the Mayor's Mansion, just as Professor Kingsford arrives. To make matters worse, Eggman catches Kingsford's attention when he takes his seat and drops a pencil. Kingsford promptly tells Eggman to recite the facts about the battle of Admiral Doom and Captain Hero. Having not expected to have read for something for the first day, Eggman cannot answer his question, prompting Kingsford to cite Eggman for his unpreparedness and label him as his goat in front of the class.
Back at the beach, Team Sonic is feeling bored, since Eggman is too busy with his studies to concoct an evil scheme for them to stop. As Sonic groans over how bored he is, Amy assures them that they can find a way to spend the time during Eggman's failure montage. Sure enough, a montage then ensues that shows Team Sonic goofing off with various activities (such as soccer, Hoverboard and Blue Force One riding, and drag racing) while Eggman struggles with his assignments in class, which are all harshly graded by Kingsford. Eventually, Eggman joins a study group that consists of his class's Lightning Bolt Society members at Dave's house. After Dave has a brief argument with his mom, the group goes over their assignments. Willy in particular asks the others if they have stolen what they were told to for lab day. Eggman reveals he just needs to steal a rubber gasket, which he intends to do covertly. Naturally, Eggman does the opposite when he steals the intended object from the Fennec Male. Noticing this, Team Sonic stops Eggman's theft (although Sonic does so with noticeably less enthusiasm than normal) by taking the rubber gasket from Eggman and playing keep away with it. Meanwhile, Willy and the Weasel Bandits watch Eggman's failure while they (with some trouble) pull off their own heist.
Back in class, Eggman and his class have assembled a rudimentary Doomsday Device as a part of a class project with the parts they have stolen. However, when Eggman reveals to Kingsford that he did not get a rubber gasket, which is essential to the device, Kingsford decides to fail his entire class, who get spiteful at Eggman. With this being the final straw, Kingsford warns Eggman that his only hope to complete the course now is to get an A on the final, a revelation which leaves Eggman in shock.
The night before the final exam, Eggman is having a nightmare due to exam anxiety. As Orbot and Cubot comes to Eggman's aid when he wakes up screaming in the middle of the night, Eggman revels in despair, certain that he will fail the exam. Choosing to ignore his "strong moral center", Eggman decides to break into the Mayor's Mansion with Orbot and Cubot and steal the answers for the exam. In spite of an excessive and troublesome spy act, Eggman manages to get the answer sheet from Kingsford's desk. The next morning, Eggman and his entire class have met up in the class room, where Kingsford has them begin the exam, which Eggman is certain that he will pass. After grading his class's papers, Kingsford reveals to Eggman in front of the entire class that his answers are all wrong. As Eggman tries to defend himself, Kingsford concludes that his student has stolen the fake answer sheet he had planted and has cheated. Eggman thinks he is trouble now for committing evil by cheating, but to his surprise, Kingsford is not upset at all. Kingsford elaborates that he is teaching a class in evil. As such, the true final exam was to steal the answers for the final exam, which Kingsford reveals that only Eggman passed to the class. Making a victory dance, Eggman leaves the class room in triumph.
Later in the Village Center, several villagers and Team Sonic have met up to witness Eggman's graduation ceremony. Upon receiving his diploma, Eggman celebrates (during which he freezes up) while the villagers leave. Meanwhile, Sonic hopes that he and his team are going to see more action next week.
- It has been mentioned by Dr. Eggman in "The Sidekick" and Orbot in "Let's Play Musical Friends" that Eggman is not a doctor.
- Team Sonic have the cars they made in "If You Build It They Will Race" (an episode that aired after "Mister Eggman").
- In "Buster", the DangerCo Deadly Equipment Warehouse is shown being located on the left side of the Mayor's Mansion, with a jungle-covered mountainside in the background and no building on its right side. In this episode however, the warehouse is situated next to a giant boulder, the mountains in the background are much further away, and a small wooden house can seen on its right side.
- When one of the Weasel Bandits is first shown at Meh Burger, he is wearing his Lightning Bowler Society uniform. In the following scenes at Meh Burger however, the Weasel Bandit is shown wearing his regular attire.
The musical segment in this episode was added to the plot because the writers thought it was an interesting way to tell the story.
Title in other languages
|Dutch||Meneer Eggman||Mister Eggman|
|French||Monsieur Eggman||Mister Eggman|
|Italian||Il corso di malvagità||The course of evil|
|Polish||Pan Eggman||Mister Eggman|
|Spanish (Latin America)||Señor Eggman||Mister Eggman|
|Ukrainian||Містер Еґмен||Mister Eggman|
|Russian||Мистер Эггман||Mister Eggman|
- Nine days before this episode aired on Boomerang, Bill Freiberger released the title card for this episode on Twitter as a teaser.
- The musical number is in the tune of "Telephone Hour" from the 1963 film Bye Bye Birdie.
- While playing keep-away with a rubber gasket after Sonic steals it from Dr. Eggman, a Yakety Sax like song started playing.
- Dave the Intern's chat with Lady Walrus during the musical number may be a nod to the friendship the two were stated to have in "Bro-Down Showdown".
- Sonic's remark about how catching rings is boring is ironic considering that collecting Rings is a major gameplay mechanic in the Sonic the Hedgehog video games, including those in the Sonic Boom series as well.
- The Doomsday Device Professor Kingsford's class was trying to assemble bears a strong resemblance to Eggman's Doomsday Device.
- Sonic's quote "Silly Eggman! Rings are for hedgehogs!" is a reference to the slogan for the Trix cereal: "Silly rabbit! Trix are for kids!".
- Eggman's mention of scary house ferns in the film "Little Shop of House Ferns" is a reference to the 1986 rock musical horror comedy film Little Shop of Horrors.
- The music that plays during Eggman's graduation is Pomp and Circumstance Marches, a series of marches for orchestra composed by Sir Edward Elgar.
- When Eggman graduates, the colors of his robe are those of  .
- Eggman suddenly freezing up after receiving his diploma is a parody of the freeze-frame shot that occurs films, usually in the last scene.
- Sonic's desire to do more stuff next week at the end of the episode is a reference to how the Sonic Boom television series airs new episodes (featuring new adventures with Team Sonic) each week during seasons.
- Sonic Boom: Mister Eggman. Zap2it.com. Retrieved on 25 June 2017.
- Bill Freiberger on Twitter. Twitter (6 July 2017). Retrieved on 7 July 2017. “Bill Freiberger: 242: When it’s revealed that Dr. Eggman is not actually a doctor, he becomes a joke and must go back to school to finish his Ph.D. in evil.”
- Bill Freiberger on Twitter. Twitter (9 July 2017). Retrieved on 10 July 2017. “Alexander Soerensen: What inspired that music segment? Was it the fans' demands for a musical episode? / Bill Freiberger: It was an interesting way to tell the story.”
- Bill Freiberger on Twitter. Twitter (29 June 2017). Retrieved on 29 June 2017. “Bill Freiberger: A #sonicboom preview for next Saturday: Ep. 242 "Mister Eggman" written by Sam Freiberger @evilsamdestroyr.”
- Bill Freiberger on Twitter. Twitter (9 July 2017). Retrieved on 9 July 2017. “Bill Freiberger: When Dr. Eggman graduates, he wears the colors of @nyuniversity. The alma mater of both the episode's author, @evilsamdestroyr, and me.”