[[caption-width-right:350:"USURPER! USURPER!"]]

Otto breaks up with his fiancee Becky at the altar, leaving her to stay at the Simpson's house, where Marge fears Becky will replace her as a better wife and mother. Meanwhile, Principal Skinner assigns Bart's class into making a video (so long as it's not a parody or rip-off of ''Film/TheBlairWitchProject''), which the school was able to afford by cutting geography lessons from their budget.

!! Tropes:

* TheAce: Becky is a great cook, a painter, knows how to stage karate moves, killed competition at a talent contest and [[HeroOfAnotherStory foiled a userper.]]
* AlwaysSomeoneBetter: Becky to Marge
* ArtisticLicenseOrnithology: Lisa states that consumption of rice makes birds swell up and explode, which is actually a myth. Wild birds are capable of eating uncooked rice without ill effects, with some species like bobolinks actually feeding on paddy fields (hence their informal term "ricebirds").
* BaitAndSwitch:
** A double when Marge learns her brakes have been cut; the window glass somehow manages to withstand the punishment, but not the largest speedbump.
** Marge looks up old newspaper clippings at the library to try to find evidence that Becky's a criminal. Every time, Marge reads only part of the headline and gasps, but then reads the rest, which clears Becky of any wrongdoing.
--->'''Marge:''' [[LampshadeHanging I really should read the whole headline before I react.]]
** At Marge's insanity hearing:
--> '''Dr. Foster:''' Marge Simpson, you give us no choice but to declare you utterly-\\
'''Marge:''' I'm not insane!\\
'''Dr. Foster:''' You didn't let me finish. ''INSANE''!
** A double one in the climax: Marge comes home, convinced Becky isn't a threat... and sees the rest of the family chained up in S&M gear as it looks like Becky is about to torture them all. It turns out Bart was filming his school project and complained about Marge entering his shot.
* BondageIsBad: Subverted, although it at least seems to be the theme of Becky's video.
* BorrowedCatchphrase: Marge takes a page out of Bart's book as she briefly strangles Becky.
--> '''Marge:''' Why you little...
* ComebackTomorrow:
--> '''Becky:''' And if you pick up some semolina, I can make couscous for Lisa.\\
'''Lisa:''' It's my favorite!\\
'''Marge:''' It is?\\
'''Becky:''' Oh, yeah. You can learn a lot from your kids if you just listen to 'em.\\
''(moments later, while Marge is driving...)''\\
'''Marge:''' Why do I always think of the perfect thing to say when it's too late? "Shut up, Becky!" Oh, that would've been ''sweet''.
* DisproportionateRetribution: [[AlternativeCharacterInterpretation If we assume Becky ''wasn't'' being sarcastic]], she would have killed Marge and stolen her family for forcing her to split up with Otto (who wasn't that good a marriage prospect, to say the least).
** At the ending, Homer fired the tranquilizer dart to knock out Marge just for being assigned to scrub and mop.
* HalfwayPlotSwitch: The first act focuses on Otto and Becky's intended wedding, up until [[UnwittingInstigatorOfDoom Marge]] gives her some advice, leading the two to ''break up at the altar''. The rest of the episode focuses on Marge's brewing envy and jealousy with Becky.
* ImprovisedWeapon: When Marge confronts Becky at the ice cream parlor:
--> '''Marge:''' Don't mess with me! I've got jimmies!\\
''(throws a handful of them at one of the employees, which hit him in the eyes)''\\
'''Employee:''' I can only see a horrible rainbow!
* IsntItIronic: Otto proposes to Becky by playing the Music/{{Poison}} song "Every Rose Has its Thorn", which is actually a breakup song.
* JerkassRealization: While explaining what Becky would do to her, Marge reminds Selma and Patty whos their brother-in-law [[note]]Homer[[/note]], making the sisters react with Patty responding, "Its an act of violence, not love."
* MistakenForMurderer: Marge was convinced by her sisters Patty and Selma that Becky will attempt to seduce her husband Homer and kill her. When Marge claiming that she's planning to murder her, this leading to her being labeled insane. Subverted when turns out Becky was trying to kill Marge(if she wasn't being sarcastic that is).
* OffModel: The character model used for Dr. Foster uses the wrong version of the character.[[note]]This episode uses the younger version of the character when explaining how he treated Ned Flanders in "[[Recap/TheSimpsonsS8E8HurricaneNeddy Hurricane Neddy]]", not the older version with grey, balding hair and aging cheeks.[[/note]]
* PoliceAreUseless: Well, they're powerless to ''protect'' Marge but not to ''punish'' her.
* ProperlyParanoid: Becky ''was'' planning to murder Marge, at least originally(unless she was being sarcastic). (She had gotten to the part where she had been making plans to bury her, but after having too much trouble buying a shovel, she decided to scrap the whole idea.)
* RightForTheWrongReasons: Selma and Patty brought up the idea that Becky was going to kill Marge, when turns out to be true had Becky not abandon the plan.
* RuleOfThree: Bart heard a rumor that Marge shows up to those who scream "Bloody Margie" three times.
* SerialKiller: While on the run, the news implies Marge as one for... reasons. [[AvertedTrope Averted with the following line]].
--> '''Bart:''' [[LampshadeHanging Kills again?]] [[ArmorPiercingResponse She hasn't killed once!]]
* ShoutOut:
** The title is a play-on to the 60s film "Film/ItsAMadMadMadMadWorld".
** The Mad Marge Dancers are a parody of the "Dancing [Judge] Itos" during the OJ Simpson trial.
** Becky wears a ComicBook/{{Vampirella}} costume in the music video.
** Patty and Selma reference ''Film/TheHandThatRocksTheCradle'' as a 'documentary film' and example of what is Becky's plan for usurping Marge's family... this deviates from being a WholePlotReference because it turns out that Becky got tired of the plan because she couldn't decide which shovel to use.
* SoapboxSadie: The whole plot happens because Marge can't stop herself from meddling with a couple's love life when she was not asked to.
* SuddenAnatomy: At the beginning of the episode, Bart tries to film a camera up Lisa's nose. [[https://frinkiac.com/gif/S11E21/112360/114960/ In the POV shot of the camera]], a nostril appears on Lisa's nose as Bart closes in.
* TooSoon: Bart's InUniverse reaction to the "Mad Marge Dancers" sketch.