Guess Who I'm Marrying

""Uh oh! Something's amiss! Or maybe even soon, A Mrs.!""

- The Narrator, Powerpuff Girls episode "Mommy Fearest"

This is a Parent with New Paramour situation in which the paramour is an obvious Devil in Plain Sight. Throughout this storyline, the parent will be firmly holding onto the Idiot Ball while their kid(s) take on the role of the Only Sane Man.

The horror will probably begin with the parent introducing the paramour to the kid(s) and providing a frightful deadline for their marriage ("This is Mr. Evil and we'll be getting married next week! Isn't that wonderful, kids?"). The paramour may be a character previously established as a Card-Carrying Villain, in which case the encounter will probably go somewhat like this:

"Mom: I've decided to get married again.

Kid: To who, Mom?

[Villain enters]

Satan McEvil: You can call me "daddy."

[Kid looks horrified. Cut to commercial break.]"

Regardless, the paramour will almost certainly behave in an obnoxious I-got-your-Mommy/Daddy-wrapped-around-my-little-finger manner throughout the scene just to make it absolutely clear from the start that they are bad. The parent, of course, will completely miss this. Once the parent is offscreen, expect the paramour to tell the kid(s) exactly what's what, usually consisting of the revelation that they are a Child-Hater and plan to send the kid(s) Off to Boarding School.

The parent will sometimes say, "I would never marry someone if you were dead set against it." And then do just that.

Of course, sometimes, the villain really does not have an evil plan regarding the marriage; they just fell for an incredibly inconvenient individual. Or they do have an evil plan, but only because they really do want to stay with their beloved forever.

Naturally, it will be up to the kid(s) to get rid of the paramour since Adults Are Useless.

And yes, it should be "Guess WHOM I'm Marrying".

Anime and Manga

 * In Akuma de Sourou (and the Taiwanese Live Action Adaptation Devil Beside You) the announcement that the heroine's mother is going to marry again isn't that traumatic... until some days later when the mother reveals that her fiancé is her daughter's school director, and that his son (a boy with whom the heroine has had some nasty clashes recently) is coming to dinner right now.
 * In Heat Guy J, Monica's mother Christina has met a man while out partying late one night, and plans to leave Judoh with him. Monica is suspicious of him, and refuses to go with them. Christina leaves with her new boyfriend anyway, thinking Monica would join them later and they'd be a family.

Comic Books

 * A Silver Age Spider-Man plot of yore centered on the nuptials of the widow May Parker and one Dr. Otto Octavius.
 * Doc Ock was actually marrying May because she was the heir to a private nuclear reactor. He didn't even realize that Spider-Man was her nephew until after he unmasked in Civil War. Brilliantly, he then went into a rant about how stupid he was not to figure it out and how he should have kept up the marriage facade for far longer.
 * An early continuity nod had Aunt May, shortly after learning Peter's secret identity, witness a fight between Spidey and Ock, and finally realise who Octavius was.
 * It is however implied that he actually likes her.
 * Played with in Ghost World. Enid is talking about her ex-stepmothers, and hates one in particular. Guess who Mr. Coleslaw's remarrying? Subverted in that the woman looks quite normal (it's been a few years) and, if I recall correctly, is actually supportive of Enid.

Film

 * Obviously, this is used in every version of The Parent Trap, leading to the Parent Trap Plot.
 * The "comedy" Mr Woodcock with the villain being a former Drill Sergeant Nasty gym teacher.
 * This Troper still wanted to see Mr. Woodcock get his ass whooped.
 * Heck, it's double subverted really. Mr. Woodcock was still an asshole too, and could not have cared less if the son had forgiven him or not.
 * Back to The Future Part II with the marriage of Lorraine Baines and Biff Tannen in 1985-A. It begins with them already married, but Marty has the typical reaction since he possesses Ripple-Effect-Proof Memory.
 * The movie Problem Child 2 had the titular kid's dad almost get married to a child-hating millionairess.
 * In this case his blindness is arguably justified. Junior had spent the earlier part of the film driving away every other date he had just because he didn't want to share his dad with anyone. Naturally, his dad is skeptical when he tries to tell him "No, this one really IS evil!"
 * Somewhat qualifies as a Family-Unfriendly Aesop: "When your kid drives away your other dates, you can't trust him anymore when the real evil woman comes along."
 * Three Men And A Little Lady but with useful adults (the three men) who are the ones who foil the antagonists plan.
 * The Night of the Hunter, in which the extremely wicked stepfather has apparently Brainwashed the mother.
 * Cpt. Vidal from Pan's Labyrinth is not the ideal stepdad, either.
 * The Disney Channel movie Mom's Got a Date With a Vampire is Exactly What It Says on the Tin.
 * Happened in Nanny McPhee: The great-aunt was willing to cough up money only if the dad married, and as the dad was almost broke, he was desperate... but he didn't quite catch the level of hate between his children and his fiancee. All the more because the kids are ridiculously ill-behaved, and so didn't quite catch the deliberately malicious undertones to their antics.
 * In a bit of a subversion, the father didn't like his fiance at all either. The only reason he was marrying her was that the alternative was the family going broke and his children being sent to work houses, or who knows where in the case of the younger ones.
 * In Disturbia, the protagonist's mother steps into the kitchen with the next-door neighbor... who the protagonist suspects is a serial killer..
 * Hank Azaria in Run Fatboy Run
 * Addams Family Values. Uncle Fester is preparing to marry a seemingly sweet woman named Debbie Jellinsky, who is actually a Black Widow, a killer who marries rich men then kills them for their money. Only Wednesday and Pugsley are wise to her true intentions, and Debbie deals with them by sending them away to summer camp.
 * Sling Blade features this trope prominently as a mentally challenged protagonist befriends a boy and discovers that the boy's mother is about to marry a man who will definitely destroy their lives. He even says so to the boy's face, though not in so many words.
 * The Ingmar Bergman film Fanny And Alexander uses this trope, though.
 * The Sound of Music has Captain Von Trapp bring Baroness Schraeder to his home to meet his children with every intention of asking her to marry him. The Baroness isn't actually all that bad, but the trope holds true from the kids' point of view since she very clearly is only interested in marrying the Captain and his money, not his seven children, who she'd just as soon pack off to boarding school. Her few interactions with the kids are highly awkward, and not surprisingly, they prefer Maria.
 * The mother in All I Want for Christmas does this, making her daughter think her wish to Santa backfired.
 * The mother in All I Want for Christmas does this, making her daughter think her wish to Santa backfired.

Literature

 * In David Copperfield, David's mother marries the nasty Mr. Murdstone.
 * Any adaptation of a fairy tale with a Wicked Stepmother is likely to use this. The Wicked Stepmother, however, is seldom a Child-Hater; she loves and jealously protects her own children (which is half the problem).
 * Some fairy tales start off with the stepmother being kind to the stepchild as well, only for things to go south when said stepchild starts to turn out prettier and more desirable than their biological children.
 * In the novel Prosperos Children, the main character finds out that her dad is marrying an evil witch.
 * Happens in Ella Enchanted, when Ella finds out that her father intends to marry the odious Dame Olga for money. She's perfectly lovely to Ella, until she finds out that Ella and her father are broke. Then it follows Cinderella straight through.
 * A variation is done in The Bad Beginning.

Live Action TV

 * A version with "adult" children occurred in Ugly Betty when Bradford announced he was marrying Wilhelmina.
 * Joyce Summers nearly married an evil robot in "Ted" on Buffy the Vampire Slayer.
 * However, Ted was actually pretty good at seeming nice, so it makes sense that he had everyone fooled. Except for Buffy, because of her tendency to take an automatic dislike to villains before she even gets evidence, combined with him threatening her when her mother wasn't around.
 * Of course, the fact that he was surreptitiously drugging everybody else didn't hurt...
 * She also went on a date with Dracula. Which apparently went well enough for him to be invited back to her place.
 * Uther Pendragon married a troll in Merlin. Disguised as an old sweetheart and enchanting him with magic, but still a troll.

Theatre

 * This is a big part of the setup for the plot of Hamlet. Though Hamlet did not know his uncle was evil until after the marriage; he just thought Uncle Claudius was an incestuous jerk for marrying his mother so soon after his father died.

Western Animation
"Bart: That man is scum!
 * A version appeared in Disney's Aladdin, except that Jasmine's father was announcing who she was marrying.
 * And he was hypnotized.
 * Selma's marriage to Sideshow Bob in The Simpsons.

Selma: Then call me Mrs. Scum."

"Chef's Mom: I gave him a dollar.
 * In an episode of The Powerpuff Girls, supervillainess Sedusa sidles her way into the Professor's life in the guise of "Ima Goodlady". Needless to say, once again, the day is saved thanks to...ThePowerpuffGirls!
 * The episode plays with the trope - the girls are perfectly happy with the Professor dating "Ima Goodlady" and even give him dating tips and encourage things as best they can. It's not until they notice that her groundings on them coincide with the nights that Sedusa robs the Mayor that they start to get really suspicious.
 * Chef almost married a succubus in an episode of South Park.
 * At least the Loch Ness monster doesn't get tree-fitty.

Chef's Dad: She gave him a dollar.

Chef's Mom: I thought he'd go away if I gave him a dollar.

Chef's Dad: Well of course he's not gonna go away, Nellie! You gave him a dollar, he's gonna assume you got more!"


 * One of Winx Club season 3's subplots was this, involving Stella's dad. They even went the "You can call me mom" route (sans ad break).
 * Amusingly, Stella's reaction differs between the two versions. Original: "Why didn't you tell me about this before?" "Because I wanted it to be a surprise." 4Kids: "Congratulations." "You don't seem too happy..." (Video.)
 * A non-parental example that's more like, Guess Whom I'm Dating, Static Shock had Virgil feel a bit like this when he found out his sister was dating a member of his Rogues Gallery: Rubber Band Man. Subverted in that she knew very well who she was seeing and they really did care about each other. Of course, the lasting power of the relationship implies that marriage will result sooner or later.
 * It does help that Rubber Band Man is one of the few Bang Babies to give up his criminal ways. He and Static even team up a few times.
 * Another example occurs in an episode where Virgil finds out that his father happens to be dating the exact same policewoman that he had a run-in with earlier. She isn't bad, but she's initially suspicious of him because he ran away in a panic when she asked to check his backpack (his Static Shock costume was inside).
 * The main character's grandfather, Puma Loco in El Tigre announces his plans to marry the main villain in one episode. Since they're both villainous, it was for their own nefarious intentions, but they eventually fell in love. Manny took a while to accept it and by the time he did, he accidentally forced them apart.
 * The Iron Giant has "Guess Who's Renting Our Spare Room", with the paranoid and crazy government agent setting up shop to spy on Hogarth while the mother is rather oblivious.
 * Her obliviousness can be justified by her very demanding work schedule, which she has to keep up to care for Hogarth and herself. The agent even brings this up at one point, telling Hogarth that his mother is under a lot of strain as a single mother and that it would be not hard to make it look like she was too neglectful to keep custody of him.
 * Done in the My Little Pony Friendship Is Magic episode "A Canterlot Wedding" with Twilight's reaction to her brother's engagement, though it's only after she's been around the bride for a bit that she suspects her of being evil - she remembered Cadence from her foalhood and immediately approved (though still resenting that Shining Armor hadn't told her before sending the invitations out). It then turns out that