Robert Underdunk Terwilliger Jr.,PhD,^[a][5] better known asSideshow Bob, is a recurring antagonist in the animated television seriesThe Simpsons. He is voiced byKelsey Grammer and first appeared in the episode "The Telltale Head". Bob is a self-proclaimed genius who is a graduate ofYale University and a champion ofhigh culture, including the adoption of atransatlantic accent, similar to that of Grammer's portrayal ofDr. Frasier Crane from the sitcomsCheers andFrasier. He began his career as a sidekick onKrusty the Clown's television show, but after enduring constant abuse, Bob framed his employer for armed robbery in "Krusty Gets Busted", only to be foiled byBart Simpson, and sent to prison. Bob started seeking revenge against Bart while in prison, and the two became feuding archenemies.

Sideshow Bob
The Simpsons character
First appearance	"The Telltale Head" (1990)
Created by	Al Jean Mike Reiss Sam Simon Matt Groening Jay Kogen Wallace Wolodarsky Brad Bird
Designed by	Matt Groening
Voiced by	Kelsey Grammer
In-universe information
Full name	Robert Underdunk Terwilliger Jr.[a]
Gender	Male
Occupation	Television personality Former Mayor of Springfield Former Mayor of Salsiccia Scientist Professor Actor Criminal
Family	Dr. Robert Terwilliger Sr. (father) Dame Judith Onderdonk (mother) Cecil Terwilliger (brother)
Spouse	Selma Bouvier (ex-wife) Francesca (ex-wife) Tasha (wife)
Children	Gino (son)
Relatives	Patty Bouvier (ex-sister-in-law) Marge Simpson (ex-sister-in-law) Homer Simpson (ex-brother-in-law) Bart Simpson (ex-nephew) Lisa Simpson (ex-niece) Maggie Simpson (ex-niece)

Bob made his second major appearance inseason three's "Black Widower"; the writers echoed the premise ofWile E. Coyote chasing the Road Runner by having Bob unexpectedly insert himself into Bart's life, threatening to disrupt and end it through murder. Starting with that appearance and thereafter, Bob has assumed the role onThe Simpsons of anevil genius. Episodes in which he is a central character typically involve Sideshow Bob being released from prison and executing an elaborate revenge plan, usually foiled by Bart andLisa. His plans often involve death and destruction, usually targeted at Bart or, less often, Krusty, though hestarts targeting the entire Simpson family inseason 17. Inseason 27, however, during the first segment of "Treehouse of Horror XXVI", entitled "Wanted: Dead, Then Alive", Bob finally gets his wish of killing Bart, commenting that he spent 24 years trying to kill a ten-year-old child; however, he becomes bored with Bart dead, so he brings him back to life so that he can repeatedly kill Bart over and over again.^[6][7][8]

Despite his villainous deeds, Sideshow Bob shares some personality traits of Grammer character Frasier Crane, and he has been described as "Frasier pickled in arsenic".^[9] Several parallels have been explicitly drawn inThe Simpsons between Bob and Frasier Crane—Bob's brother Cecil and his father were played byDavid Hyde Pierce andJohn Mahoney, respectively, echoing the roles they played inFrasier. Grammer, who based Bob's voice on that of actorEllis Rabb, has been praised for his portrayals of the character. In 2006, he won an Emmy forOutstanding Voice-Over Performance for his work in the episode "The Italian Bob".

As of season 36, Sideshow Bob has appeared in more than 40 episodes, had speaking appearances in 25 of these, and been featured as the main character in 15. The most recent of the latter, "The Yellow Lotus", aired duringthe 36th season, and his most recent speaking appearance was in "Treehouse of Horror XXXIV" inthe 35th season.^[10] In addition to his recurring role in the series, Sideshow Bob has made several appearances in otherSimpsons media and is mentioned in several more episodes. He appears in theSimpsons Comics, the 2007 video gameThe Simpsons Game, and stars as the main antagonist inThe Simpsons Ride at Universal Studios' theme parks. A lover ofGilbert and Sullivanoperettas, Sideshow Bob is also known for his singing voice; several of Grammer's performances have been included inThe Simpsons musical compilations.

The character of Sideshow Bob began his career as the non-speaking sidekick who would only use a whistle onKrusty the Clown's television show.^[11] Bob first appears in "The Telltale Head" (season 1, 1990). In the episode, he and Krusty plan a big event for whoever knows information of who captured the head of Jebediah Springfield's statue, and joins in on the town mob when it is discovered thatBart Simpson took it. However, after repeated instances of abuse, including beingshot from a cannon andhit constantly with pies, theYale-educated Bob became angry with Krusty and resentful of the clown's success.

In "Krusty Gets Busted" (season 1, 1990), Bob disguised himself as Krusty and framed him for armed robbery of theKwik-E-Mart. After Krusty is arrested, Bob takes control of the show, introducing children to elements ofhigh culture. However, Bob's reign is short-lived; Bart exposes him as the robber, Krusty is released, and Bob is fired and sent to jail.^[12]

In "Black Widower" (season 3, 1992), Bob's first major appearance after framing Krusty, he is released from prison and marries Bart's auntSelma Bouvier as part of a scheme toinherit money she hasinvested in thestock market. Bob attempts to blow Selma up during theirhoneymoon, but Bart again foils the plan and Sideshow Bob returns to prison.^[13]

After beingparoled from prison in "Cape Feare" (season 5, 1993), Bob targets Bart directly, threatening him repeatedly and forcing the Simpsons into hiding as part of theWitness Relocation Program. Bob follows them to their hideout, ahouseboat on Terror Lake, and, after subduing the family, prepares to kill Bart. He allows a final request, however, and Bart asks to hear Bob sing the entire score ofH.M.S. Pinafore. Although Bob finishes singing and nearly kills Bart, the delaying tactic leads to Bob's third arrest as the houseboat had drifted all the way back to Springfield.^[14]

Bob is released from prison once again in "Sideshow Bob Roberts" (season 6, 1994), and runs for Mayor ofSpringfield as theRepublican Party candidate. He defeatsDemocratic Party incumbentJoe Quimby in a landslide, but Bart and Lisa discover fromWaylon Smithers that Bobrigged the election by using the names of deceased people. Bob is put on trial and claims himself innocent, but is tricked by Bart and Lisa to expose himself guilty, leading to another incarceration.^[15]

Sideshow Bob escapes from prison for the first time in "Sideshow Bob's Last Gleaming" (season 7, 1995), and threatens to blow up Springfield with anuclear bomb unless the city stops broadcasting all television shows. He is thwarted when he finds out that the bomb itself is a dud, then kidnaps Bart and flies theWright Brothers' plane in an attempt to kill himself, Bart, and Krusty (who is hiding inside a shack, improvising a performance on theEmergency Broadcast System). This too is thwarted, and Bob returns to prison.^[16]

In thefollowing season, Bob takes advantage of the prison'swork release program, and appears to be genuinely redeemed. "Brother from Another Series" (season 8, 1997) reveals that Bob only became Krusty's sidekick after his younger brotherCecil failed an audition ten years prior, because Krusty considered Bob to be a perfectcomic foil.^[17]Reverend Lovejoy declares him a changed man and recommends him for awork release opportunity. Bob is discharged from prison into the care of Cecil, who is nowSpringfield's chiefhydrological and hydrodynamical engineer. However, the scheming Cecil, still smarting over his failed audition for Krusty, tries to frame Bob bysabotaging the Springfield Dam by having it burst across Springfield. Bob, Bart, and Lisa together stop Cecil and save the town, and both brothers, despite Bob's genuine innocence, are sent to prison.^[17]

Bob returned in "Day of the Jackanapes" (season 12, 2001), where he discovers in prison that Krusty has erased all of the early shows featuring Sideshow Bob as Krusty himself is declaring his fifth and final retirement after being annoyed with thenetwork executives. Bob is released from prison and develops a plot to kill Krusty using Bart as asuicide bomber during Krusty's retirement special. Everything goes just as Bob had planned, and just when Bob was about to succeed in murdering both his enemies, he overhears Krusty publicly holding himself responsible for turning Bob into a criminal, expressing his regret of mistreating Bob during his years as Sideshow. To appease things, Krusty sings himself a song on Bob's behalf, and being touched by this, Bob decides to abort his plan ofattempted murder and reconciles with Krusty, although he is returned to prison for it.^[18]

Bob's aid is sought by Springfield police in "The Great Louse Detective" (season 14, 2002). After an attempt is made onHomer Simpson's life, Bob is released from prison to help find the culprit. During the adventure, Bob is given advice to kill Bart without hesitation, instead of being tricked into delay or screwing up on his plots. When the mystery is solved (it wasFrank Grimes's son), he returns to murder Bart. However, Bob finds he is "accustomed to his [Bart's] face" and cannot do it.^[19]

In "The Italian Bob" (season 17, 2005), it is revealed that Bob had moved toItaly to make a fresh start. He was eventually elected mayor of the village of Salsiccia inTuscany and marries a local woman namedFrancesca, with whom he has a son namedGino. The Simpson family, in Italy to retrieve a car forMr. Burns, encounters him by chance. Bob welcomes them with hospitality on the condition that they not reveal his dark felonious past; however, a drunken Lisa jokes about Bob's criminal deeds and reveals his prison uniform, alienating Bob from his citizens. Bob is angered enough to change his dream of killing Bart to killing the whole Simpson family. Upon catching up to Bob, his wife and his son swear avendetta with him on all the Simpsons.^[20]

The entire Terwilliger family returns in "Funeral for a Fiend" (season 19, 2007) in which Bob's father, Robert Terwilliger Sr., and mother, Dame Judith Onderdonk, make their first appearances.Cecil also appears a second time on the show. Bob at first attempts to kill the whole family a second time, but his plan fails. Bob fakes his own death during his trial and locks Bart in thecoffin, which he attempts tocremate at the otherwise emptyfuneral home as all the Terwilligers laugh maniacally. They are foiled by Lisa and the rest of the Simpson family and sent to prison.^[21]

In "Sex, Pies and Idiot Scrapes" (season 20, 2008), Bob is one of the wanted criminals in Homer andNed Flanders's bounty hunter job despite already being in prison, which he escapes from at the end of the episode. In "Wedding for Disaster" (season 20, 2009), Bart and Lisa initially suspect Bob of kidnapping Homer to prevent him from attending hissecond wedding withMarge (due to a keychain they found had an 'S' and a 'B'), but Krusty provides him with an alibi, explaining to the kids that Bob was with him the whole day. Eventually, Bob and the kids discover the true culprits,Patty and Selma.^[22]Bob also appears in “Coming to Homerica”, the 21st episode of Season 20, in a joke where the Simpson family enters the Cheers bar dressed as the Cheers cast when Sideshow Bob comes in dressed asFrasier Crane.

In "O Brother, Where Bart Thou?" (season 21, 2009), Bob makes a non-speaking cameo appearance in Bart's dream sequence while the latter becomes desperate of having a younger brother.Cecil makes his third appearance inThe Simpsons by appearing alongside Bob; the brothers are flying kites together. Bob reappears again in the episode "The Bob Next Door" (season 21, 2010). He switches faces with his prison cellmate Walt Warren. Bob returns to Springfield and moves into the house next to the Simpson family, assuming Walt's identity. He exploits this to make his latest attempt to kill Bart legally over state lines, but is foiled again and gets taken away bystate police.^[23]

Bob appears in "At Long Last Leave" (season 23, 2012), the 500th episode ofThe Simpsons. He attends atown meeting to decide if the Simpson family should bebanished from Springfield, and is one of many who express their desire for it to happen.^[24] He makes a silent appearance in "Moonshine River" (season 24, 2012), where he runs across the train tracks trying to kill Bart, but ends up getting hit by a train.

In "The Man Who Grew Too Much" (season 25, 2014), he was revealed to be a Chief Scientist for agenetic engineering company namedMonsarno, having received the position after he was selected as atest subject and published the results of the experiments to which he was subjected. He and Lisa bond over their interest inWalt Whitman, but Bob reveals that he has also genetically modified himself to give himself varioussuperhuman abilities, intending to acquireDNA from the relics of varioushistorical figures stored in the Springfield Museum to make himself a superhumandictator. After tempted into a murderous rage, he chases down Bart and Lisa and is about to kill them but however, he is provoked into a fight and he realizes that he has become a crude monster and jumps off the Springfield Dam. The episode ends with Bob underwater in the lake, shown to have survived because thegills he gave himself allow him to live.

Bob also appears in "Clown in the Dumps" (season 26, 2014). Having returned to prison, he offered his condolences to Krusty after the death of his father,Rabbi Krustofsky. Several episodes later, Bob returned in "Blazed and Confused" (season 26, 2014), where he meets Mr. Lassen, Bart's former teacher, who was now reduced to working in prison as aguard after Bart's earlier actions at a "Blazing Guy" festival got him fired. Despite Lassen's offer to get him out, Bob rejects the idea that they team up as Lassen thought that they would take turns gutting Bart.

In "Treehouse of Horror XXVI" (season 27, 2015), in the first segment called "Wanted: Dead, then Alive", Bob usesMilhouse's phone to trap Bart in the band classroom and successfully kills him. In peace with himself, Bob moves on from Bart to pursue other dreams, however, due to Bob chasing down Bart for so long, Bob finds his life so meaningless in Bart's absence that he creates a machine to bring Bart back to life so that he can keep killing his enemy over and over, until the other Simpsons find Bob's location and rescue Bart, and Bart uses the resurrection machine to turn Bob into a twisted amalgamation of creatures. Bob also appears in the episode "Gal of Constant Sorrow" (season 27, 2016), grunting in annoyance as he wipes off Bart'sgraffiti from Hettie Mae Boggs' promo poster on the wall along withSnake Jailbird and other inmates.

Bob returns in "Treehouse of Horror XXVII" (season 28, 2016), the 600th episode ofThe Simpsons. In the opening sequence, he is the self-appointed leader of a four-member group consisting of Homer's enemies, including Bob himself and the ghost of Frank Grimes. Wanting revenge once more, the group attempts to kill the Simpsons but is ultimately killed byMaggie, except Grimes's ghost. In the ending sequence, Bob is one of the characters featured in the "600" song played byJudith Owen. In "Havana Wild Weekend" (season 28, 2016), Sideshow Bob appeared in the backgrounds at the Cuba's check-in.

Bob also makes a non-speaking cameo appearance in "The Nightmare After Krustmas" (season 28, 2016); he is amongst the crowd witnessing Krusty nearly drowning in a frozen lake while holding up a sign saying "Die Clown". He's had a major appearance in "Gone Boy" (season 29, 2017), when he tries to track down the whereabouts of Bart after he goes missing and is presumed dead. Bob finds Bart and proceeds to kill him andMilhouse, but saves them at the last minute due to the influence of the prison therapist's lessons of potentially moving on from wanting to kill Bart. The epilogue features an older Bob, now known as Elder Bob, being a lighthouse keeper and still having regrets of not killing Bart.

In "The Fat Blue Line" (season 31, 2019), Bob escapes from prison once again, only to be hit by a rake truck. Several episodes later, in "Bobby, It's Cold Outside" (season 31, 2019), he is hired to play Santa Claus at a theme park, and later helps the Simpsons discover who is stealing everyone's Christmas gifts. Bob returned in a non-speaking cameo in "Meat Is Murder" (season 33, 2022), where he is seen signing the chests of citizens like Milhouse's fatherKirk Van Houten at the celebration ofKrusty Burger's 50th anniversary, a callback to the "Die Bart, Die" scene from "Cape Feare".

In the "Treehouse of Horror XXXIV" segment "Ei8ht" (season 35, 2023), in an alternative ending to "Cape Feare", Bob realizes that Bart is stalling his death by making him singPinafore, and as a result, kills him, traumatizing Lisa. 30 years later, the Springfield Police asks Professor Lisa Simpson to look into a series of murders committed by an unknown serial killer. Perplexed, Lisa seeks Bob's help, but Bob just mocks Lisa. Later, Lisa realizes she herself has done all the murders. Bob is transferred to another prison cell to find Lisa waiting for her, revealing that a split personality emerged after the death of Bart and that she had committed all those murders in hopes of going to prison with Bob. To the music ofH.M.S. Pinafore, Lisa gleefully slashes Bob to death.

In Season 36’s “The Yellow Lotus”, Bob has a minor role, as he is shown to be married and in the same resort with the Simpsons. When Marge tells Bob’s wife about his previous deeds, she throws him off of a cliff, only for Bob to survive and talk with Sideshow Mel.

In addition to regular roles in the television series, Sideshow Bob has made several appearances in otherSimpsons media. Kelsey Grammer recorded several Sideshow Bob lines forThe Simpsons Movie, but the scene was cut; the deleted scene shows him amongst the angry mob, intent on killing Bart until he learns that the mob is apparently after Homer only, prompting him to leave in disappointment.^[25] Sideshow Bob has made regular appearances in the monthlySimpsons Comics,^[26] and several of Kelsey Grammer's singing performances have been included inThe Simpsons CD compilations. His performance of theH.M.S. Pinafore in "Cape Feare" was later included on the albumGo Simpsonic with The Simpsons,^[27] and the song "The Very Reason That I Live" from "The Great Louse Detective" was included onThe Simpsons: Testify.^[28] A previously unaired song, "Hullaba Lula", originally written for "Day of the Jackanapes", was also included on that compilation.^[28] The producers modeled the song after "Zip-a-Dee-Doo-Dah", but were forced to remove the song from the episode when they were unable to obtain the rights to it.^[29]

InThe Simpsons Game, released in November 2007, Bob has a speakingcameo appearance at the end of the chapter titled "Invasion of the Yokel-Snatchers" in which he was working withKang and Kodos.^[30] Sideshow Bob appears in the 1991The Simpsons Arcade Game, on the fifth level where he is pulling a cart containing a roast chicken health pick up. Bob was also included as a level boss in the 1991 video gameBart vs. the Space Mutants.^[31] Sideshow Bob plays a lead role inThe Simpsons Ride, which opened atUniversal Studios Florida andUniversal Studios Hollywood in May 2008. Voiced by Grammer, he is the main villain in the ride, having escaped from prison to get revenge on the Simpson family.^[32][33]

InThe Simpsons: Tapped Out, acity-building game released in February 2012, Sideshow Bob occurs as a bonus. Popping up every couple hours, the players are given a chance to tap on him to receive a small sum of money, and "send" him to jail. In a later update to the game, Sideshow Bob also has a stand in Krusty Land, where players get to pop balloons for a chance to win donuts and Krustytickets. The Simpsons: Tapped Out Terwilligers content update was released April 14, 2015 and has several references to the Simpsons episodes with Sideshow Bob. This game event was split in 3 acts and ended June 4, 2015. New characters, skins and costumes include Sideshow Bob, Cecil Terwilliger, Gino Terwilliger, Francesca Terwilliger, Dr. Robert Terwilliger Sr., Judith Onderdonk, Captain Bob, and Opera Krusty. Most of the event action takes place at Monsarno Research and Opera House.

Sideshow Bob first appeared in "The Telltale Head", the eighth episode ofseason 1. His design was relatively simple compared to later incarnations, and his hairstyle was rounded. However, towards the end of the episode, he appears again, in a panning shot of a crowd, with his familiar hairstyle.^[34] His second appearance, and first major one, was in season 1's twelfth episode "Krusty Gets Busted", written byJay Kogen andWallace Wolodarsky.^[35] Bob's design was updated for "Krusty Gets Busted"; as the episode's animation style evolved, directorBrad Bird made the character of Sideshow Bob sleeker and more refined, to fit Grammer's voice technique.^[36] Following the re-design, animators tried to redraw his scenes in "The Telltale Head", but had insufficient time before the show was produced.^[34]

Bob has no lines of dialogue during the first half of "Krusty Gets Busted"; the character's only communication takes the form of aslide whistle. This was designed to make Bob appear simplistic, so that when he finally spoke, viewers would be surprised to hear his sophisticated vocabulary.^[37] An early version of the script for "Krusty Gets Busted" called forJames Earl Jones to voice Bob, but the producers instead selectedKelsey Grammer.^[38] For Bob's voice, Grammer performed an impression of theatreactor anddirectorEllis Rabb. Grammer had once worked for Rabb, whose "lamenting tones became [the] foundation for Sideshow Bob".^[39][40]

Sideshow Bob's full name is Robert Underdunk Terwilliger.^[41] Hislast name was first revealed in "Black Widower"^[13] while hismiddle name was first revealed in "Sideshow Bob Roberts".^[15] Competing theories as to the origin of his name exist; some sources say he was named after the character Dr. Terwilliker, a megalomaniac outwitted by a boy named Bart in the filmThe 5,000 Fingers of Dr. T byDr. Seuss, but others say he was named afterTerwilliger Boulevard inPortland, Oregon.^[42][43][44] Yet another theory is that he was named after Sergeant Terwilliger and Mrs. Onderdonk in the pilot episode of the TV showHunter.^[45]

Forseason three's "Black Widower", the writers echoed the premise ofWile E. Coyote chasing the Road Runner fromLooney Tunes cartoons by having Bob unexpectedly insert himself into Bart's life and attempt to kill him. Executive producerAl Jean has compared Bob's character to that of Wile E. Coyote, noting that both are intelligent, yet always foiled by what they perceive as an inferior intellect.^[46] For "Black Widower", directorDavid Silverman updated the character model to reflect the animation of director Brad Bird.^[36] A rule for earlier episodes featuring Bob called for a recap of his evil deeds; this was dropped afterseason eight's "Brother from Another Series" when the chronology became too lengthy.^[47] Another rule established by the show's writers mandated Bob's return to prison at the end of each episode, although this pattern was abandoned in later episodes like "The Great Louse Detective" and "The Italian Bob".^[47]

Bill Oakley andJosh Weinstein, theshowrunners for the seventh and eighth seasons, believed that every season of the show should contain an episode starring Sideshow Bob. However, by the seventh season, Bob had already been the focus of four episodes, and writers were having trouble developing new ways to include him.^[48] Weinstein describes Bob's dialogue as difficult to write, due to his unique and refined style of speaking.^[49] Despite these challenges, however, creators ofThe Simpsons usually look forward to "Sideshow Bob episodes"; the writers consider them enjoyable to write,^[50] and former directorDominic Polcino describes them as "a treat" to work on.^[51] In "Black Widower", Sideshow Bob notes that he is a "life-longRepublican".

Kelsey Grammer initially expected Sideshow Bob to be a one-time role, and calls him "the most popular character I've ever played".^[39] Grammer usually joins the show's "table readings" (wherein cast members read each script together for the first time),^[52] and former executive producerDavid Mirkin described working with Grammer as very pleasant, due to his lively sense of humor. Grammer, Mirkin says, is capable of perfect readings, but noted that the actor dislikes performing Sideshow Bob's evil laugh.^[53] In a 2007 interview,Simpsons executive producerAl Jean listed Grammer as one of his favorite guest stars (second only toPhil Hartman), saying "his voice is so rich."^[54] WriterGeorge Meyer commented that "writing for Kelsey is great, he can give the kind of purple, florid, melodramatic speeches that most of the characters would never give. And he can sing."^[55]

The show's writers admire Grammer's singing voice, and try to include a song for each appearance.^[52]Alf Clausen, the primary composer forThe Simpsons, commented that "[Grammer] is so great. He's just amazing. You can tell he has this love of musical theater and he has the vocal instrument to go with it, so I know whatever I write is going to be sung the way I've heard it."^[56] Clausen composed Sideshow Bob's theme, which is played whenever Bob gets out of prison or is about to commit a sinister action, and was first used in "Cape Feare". It is based on the score of the filmCape Fear, composed byBernard Herrmann.^[52] The musical score for "Cape Feare" earned Clausen anEmmy Award nomination forOutstanding Dramatic Underscore – Series in 1994.^[57]

Bob's prisoner number is often 24601, which isJean Valjean's prisoner number inLes Misérables.^[58] Another trademark for Bob is a visual gag of stepping on a rake and being struck in the face with its handle; this joke first appeared in "Cape Feare". To fill time, the writers added nine consecutive iterations of the same joke in quick succession.^[52] The sequence has become known as the "rake joke" and was described byEntertainment Weekly as showing "genius in its repetitive stupidity."^[59]

The episode "Brother from Another Series" introduces Bob's brother Cecil. After writerKen Keeler was assigned to write an episode featuring Sideshow Bob, he drew inspiration from episodes ofFrasier. He decided to incorporate elements of Grammer's other show into the character of Sideshow Bob, and designed Cecil to resemble Grammer's brother onFrasier.^[50] Cecil is voiced byDavid Hyde Pierce, who portrayedFrasier Crane's brotherNiles. Pierce commented, "Normally, I would not do something like this. But how often do you get a chance to work with an actor like Kelsey Grammer and, more importantly, play his brother?"^[60] Several ofFrasier's producers were asked to review the original script and provide feedback. Their comments were positive; they only expressed concern with a very brief scene in which Cecil talks to a visible character whom he refers to as "Maris". InFrasier,Maris Crane is anunseen character, and the producers ofFrasier asked that the scene be removed.^[50] Many of the interactions between Bob and Cecil were based on those of Niles and Frasier.^[50] Cecil was drawn to resembleDavid Hyde Pierce, while retaining a visual similarity to Sideshow Bob. According to directorPete Michels, it was difficult to draw Bob and Cecil standing together, because of their comically oversized feet.^[61]

Cecil returns inseason 19's "Funeral for a Fiend", which introduces the brothers' previously unseen father, Dr. Robert Terwilliger, played byJohn Mahoney.^[62] Mahoney portrayedMartin Crane, the father of Grammer's and Pierce's characters inFrasier.^[63] Whereas inFrasier, Mahoney played the "down-to-Earth, average guy" to Grammer's and Hyde Pierce's "uppity snobs", Robert Terwilliger Sr. was portrayed as equally highbrow as Bob.^[64] His wife, Bob's mother, is Dame Judith Onderdonk, "the finest classical actress of her generation." She sports the same curly spiked hair as her two sons. Bob also has a wife named Francesca (voiced byMaria Grazia Cucinotta) and a son named Gino, both of whom were introduced inseason 17 episode "The Italian Bob" and returned for "Funeral for a Fiend".^[20]

The character of Sideshow Bob and Grammer's voicework have received many accolades. In 2006,IGN listed him as the second-best "peripheral character" onThe Simpsons, commenting that Bob is "a man of contradictions; his goofy appearance, complete with palm tree like hair, doesn't seem to match up to the well spoken and even musically talented maniac."^[66] Also that year,Wizard magazine rated Bob as the 66th-greatest villain of all time.^[67] Adam Finley ofTV Squad wrote that "that baritone voice, the Shakespearean delivery, and the ability to go from calm and collected to stark raving mad all within the same second make Sideshow Bob one of the best recurring characters on the show."^[68]

Kelsey Grammer has consistently received praise for his voicework, and has been described as "brilliant",^[69] "inimitable"^[70] and "a feast of mid-Atlantic anglophilia".^[71] In 2006, Grammer won thePrimetime Emmy Award forOutstanding Voice-Over Performance for his role in "The Italian Bob"; he had previously won four awards in theOutstanding Lead Actor in a Comedy Series category for his portrayal of the title role onFrasier.^[72] In 2008, Grammer was included inEntertainment Weekly's list of the sixteen bestSimpsons guest stars; Hyde Pierce was also included in that list.^[73] Ken Tucker ofEntertainment Weekly wrote that "Kelsey Grammer's grand voice-performance as Sideshow Bob is Frasier pickled in arsenic."^[9] In her bookMy Life as a 10-Year-Old Boy,Nancy Cartwright (who performs the voice of Bart Simpson) wrote that "Kelsey Grammer scores big-time by injecting caustic, bitter, contemptuous and deliciously vile energy into his rendition of Sideshow Bob. Springfield just wouldn't be the same without him."^[65]

Most of the episodes featuring Bob have been well received by fans and critics. "Cape Feare" is generally regarded as one of the best episodes ofThe Simpsons^[74] and placed third onEntertainment Weekly's 2003 list of the show's top 25 episodes.^[59] IGN considers it the best episode of the fifth season.^[75] In 2007,Vanity Fair called it the show's fourth-best episode, because of its "masterful integration of filmic parody and a recurring character".^[76]Ben Rayner of theToronto Star listed "Cape Feare", "Sideshow Bob's Last Gleaming" and "Brother From Another Series" among the best episodes of the series, writing "forgetFrasier, these are Kelsey Grammer's best roles."^[77] "The Italian Bob" and its writerJohn Frink won aWriters Guild of America Award in 2007 in the animation category.^[78] In December 2009, Robert Canning of IGN ranked the ten episodes to feature Bob that had aired at the time. The first five Bob episodes took up the top five, with "Cape Feare" being ranked first. "The Italian Bob" was ranked tenth, with the explanation that "All the things we love about a Sideshow Bob episode—the vengeance, the familiar settings and characters, the elaborate scheming—were missing from this half-hour. Without it, Bob wasn't nearly as entertaining, and the episode didn't result in a whole lot of laughs." He noted that only "The Italian Bob" and the ninth ranked "Funeral for a Fiend" were "the only ones I'd consider clunkers. The remaining episodes are all quite fun."^[79]

The character's line in "Sideshow Bob Roberts", "Attempted murder? Now honestly, what is that? Do they give a Nobel prize for attempted chemistry?", briefly became anInternet meme after a similar defense of PresidentDonald Trump was repeated after theTrump–Ukraine scandal.^[80]

InPlanet Simpson, authorChris Turner writes that Bob is built into a highbrow snob and conservativeRepublican so that the writers can continually use him as a strawman and pincushion. He representshigh culture while Krusty representslow culture, and Bart, stuck in between, always wins out.^[71] In the bookLeaving Springfield, David L. G. Arnold comments that Bart is a product of a "mass-culture upbringing" and thus is Bob's enemy.^[81] Frustrated by his early role as the target of "Krusty's cheap gags", Bob frames Krusty and takes over the show. He changes the content of that show to present readings of classic literature and segments examining the emotional lives of pre-teens. He believes that by exposing the kids to high culture he will improve their lives.^[82] Arnold writes that "Bob's own conscience and morality are clearly unaffected by the high culture he represents." He also tries to "manipulate the tastes of the masses" by becoming a criminal mastermind.^[82] Arnold believes that this is most apparent in "Sideshow Bob Roberts", wherein he rigs the election to become the mayor of Springfield. When accused of election fraud, he rants, "Your guilty consciences may force you to vote Democratic, but secretly you yearn for a cold-hearted Republican who'll cut taxes, brutalize criminals, and rule you like a king! That's why I did this, to protect you from yourselves!" He considers himself a member of the social elite, and happily usesMachiavellian methods to acquire and maintain power.^[83]

Bob's intelligence serves him in many ways. During the episode "Cape Feare", for example, the parole board asks Bob why he has a tattoo that says "Die, Bart, Die". Bob replies that it is German for "The, Bart, The"; members of the board are impressed by his reasoning.^[84] Believing that "nobody who speaks German could be an evil man", they release him.^[14] However, his love of high culture is sometimes used against him. In the same episode, Bob agrees to perform the operettaH.M.S. Pinafore in its entirety as a last request for Bart. The tactic stalls Bob long enough for the police to arrest him.^[84]