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 ''The Blair Witch Project''), 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
* BaitAndSwitch: 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.
** At Marge's trial:
--> '''Judge''': Marge Simpson, you give us no choice but to declare you utterly-\\
'''Marge''': I'm not insane!\\
'''Judge''': 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.
* 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''.
* 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.
* OutOfCharacterMoment: Some fans hated this episode because Marge was jealous of Becky for no reason (other than her sisters scaring her into thinking that having Becky in the house will turn her life into ''Film/TheHandThatRocksTheCradle'') and tried to attack her.
* PoliceAreUseless: Well, they're powerless to ''protect'' Marge but not to ''punish'' her.
* 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 "Mad Marge" three times.
* ShoutOut:
** The title is a play-on to the 60s film "ItsAMadMadMadMadWorld".
** The Dancing Marges is a parody of the "Dancing [Judge] Itos" during the OJ Simpson trial.
* TooSoon: Bart's InUniverse reaction to the "Dancing Marges" sketch.