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Fanfic / Ultrasonic

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Ultrasonic is a complete crossover fanfic between Miraculous Ladybug and Zootopia, written by SmashGenesis and published at Archive of Our Own.

Several years after the first case of his career, Nick finds himself dealing with a certain juvenile delinquent far more often than he'd like: One Marinette Dupain-Cheng. But after a devastating turn of events, Nick and Marinette find that they need each other's help, for the fate of two worlds depends on them.


Ultrasonic contains examples of

  • Animorphism: Marinette is turned into a white cat upon arriving in Zootopia, though she turns back to her human form while transformed into Ladybug.
  • Antagonist Title: As with nearly every Miraculous episode.
  • Arbitrary Skepticism: Subverted by Chief Bogo, who takes Marinette's explanation about akumas and the Miraculous in stride, saying that he's willing to suspend disbelief a bit after what's happened tonight. Played straight with Mayor Swinton, who dismisses Marinette as a delusional teenager and refuses to let Bogo release her.
  • Badass Normal: Nick, when he insists on partnering with Ladybug in the final confrontation with Ultrasonic despite having no Miraculous of his own.
  • Bittersweet Ending: Ultrasonic is defeated and Zootopia is saved, and while the Butterfly is still out there and still as powerful as ever, he's implied to have given up in despair. Nick has been fired from the ZPD, but he avoids jail time for his actions during the crisis and is happy as long as Judy is safe - they get engaged in the last scene. As for Marinette, she finds a new home with Clawhauser and, in contrast to her self-destructive behaviour over the past year, she is willing to make the best of things in Zootopia. But it doesn't change the fact that Adrien is dead and she may never see Alya or her parents again.
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  • Break Them by Talking: Plagg to the Butterfly. "Adrien was a good kid, and he was a good Miraculous holder, too. You, though? You use your Miraculous for selfishness and evil. You’re a sad, pathetic shell of a man who can’t accept defeat with grace. You think you can beat Ladybug? You think you have a chance of seeing your ‘dearest wish’ come true? That’s about as likely as me not enjoying a good piece of cheese. Face it: You’re never going to win."
  • Calling Me a Logarithm: When Nick describes the situation in the city as a pandemonium, the polar bear driving him objects, saying he has relatives who are pandas. Nick tells him to pick up a dictionary.
  • Comes Great Responsibility: Marinette decides to have Ladybug join the call for Mayor Bourgeois's resignation, expecting a lecture from Tikki about using her powers for personal gain. Tikki surprises her by saying that stopping Chloe from using her father's power as a threat is exactly what Ladybug should be doing to help people.
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  • Dare to Be Badass/You Are Better Than You Think You Are: Tikki trying to break Marinette out of her funk after the first Ultrasonic attack. "I’m upset because you’ve given up. First, you’d given up on ever being happy in this world, and now you’ve given up on beating this supervillain, and most of all, you’ve given up on yourself! You always used to say you were a ‘girl like any other,’ but you have such incredible power within you, not just as Ladybug, but as Marinette, too! Yes, the situation seems hopeless, but I believe in you!"
  • Darkest Hour: By the end of Chapter 13, there are an army of Ultrasonic clones, all powered up by the Black Cat Miraculous, all ready to raze Zootopia to the ground if the Butterfly doesn't get what he wants, and the only people in position to stand in their way are Ladybug and Nick Wilde.
  • Dead Partner: Chat Noir.
  • Department of Child Disservices: Played with. Marinette has been in the foster care system for nearly a year when the story opens, and has been shuffled out of two homes as a result of her repeated runaway attempts. We don't learn a lot about the first two sets of parents, but we do know that the first had her moved on immediately after the first runaway, while the second seem to have stuck with her a while longer before she was placed with the Whites. But in any case, we know she wasn't running away because of any problem with the homes, but because she was determined to find a way back to Paris, and the worst we actually see from the Whites is Luna's harsh attitude when she picks Marinette up from the precinct, which Art tries to talk her down from, and her decision to have her moved on again after her she gets arrested again during the Ultrasonic crisis, though there's no indication that they know she was responsible for ending it.
  • "Eureka!" Moment: During the climax, Ladybug remembers Tikki telling her that the Butterfly had to be in Zootopia to akumatise Clawhauser, leading her to realise that his threat to raze Zootopia is a bluff.
  • Fired Teacher: After Miss Mendeleiev fails Chloe on a chemistry test, she arranges for her father to force Principal Damocles to fire her under threat of a severe budget cut. Alya records the confrontation and posts it online in an attempt to rally Paris against the mayor, with some success - but not before Miss Mendeleiev gets akumatised over it.
  • Fish out of Water: Marinette. Even after a year in Zootopia, she finds it hard to get used to.
  • Gorn: The description of Adrien's body.
  • Guilty Pleasure: Nick's interest in Reality TV, as long as it's a talent contest of some kind.
  • Hero Insurance: Played with. While the Ultrasonic crisis ends with Ladybug repairing the damage as usual and no apparent loss of life, Nick loses his job for his role in the jailbreak (probably not helped by the fact that he was already suspended), but he does escape any charge beyond Misdemeanour Obstruction of Justice - Judy states that no jury would convict him. Likewise, while Marinette was previously in trouble for her interference in the first Ultrasonic attack, she avoids those charges thanks to saving the day, and it appears any lingering consequences from her previous runaway attempts, such as the curfew, have been lifted due to her willingness to work with the police as Ladybug.
  • Hostage for MacGuffin: Nick gets captured by an Ultrasonic clone during the climax and used as leverage for the Ladybug Miraculous. Instead, he bites his captor on the arm and frees himself.
  • I Choose to Stay: After learning that her path home may cause Zootopia to cease to exist, Marinette decides that she can't take that risk.
  • Inelegant Blubbering: A few times with Marinette, in particular when she breaks down while searching for the Butterfly's hideout just before she gets transported to Zootopia, and later after her failure against Ultrasonic.
  • I Work Alone: Just before the climax, Ladybug insists on going in alone, not wanting to risk a repeat of what happened to Chat Noir. Nick manages to convince her otherwise, figuring out that she's never done this without a partner and reminding her that he's doing this to save his partner.
  • Kick the Dog: Two examples, both leading to akumatisations:
    • Simone Cowl's humiliation of Clawhauser inThe Z Factor live show, praising his performance before rejecting him solely because of his weight.
    • The flashback has one from Chloe (naturally), when she uses her father's influence to get Miss Mendeleiev fired over a bad result on a chemistry test.
  • Kill It with Water: Ladybug's defeat of Ultrasonic and his clones at the concert hall involves setting off the sprinkler system and shorting out their microphones.
  • Language Barrier: There doesn't seem to be a language barrier between Marinette and Zootopia. Likely justified if Tikki's Lucky Charm theory is correct.
  • Lawful Stupid: Judy's insistence on keeping the akumatised microphone as evidence, despite realising that Ladybug understands more about what's happening than she does, results in the akuma getting away.
  • Let's Get Dangerous!: Nick resolving to fix the Ultrasonic situation after his conversation with Finnick.
  • Love Confession: Between Nick and Judy, the morning after the first Ultrasonic attack, right before Judy gets transformed.
  • Make Me Wanna Shout: Ultrasonic's power, not too surprisingly. Thanks to a power-up from the Black Cat Miraculous, he's stated to be the most destructive akuma Ladybug has ever faced, even before there's an army of him. However, his powers are weakened if the targets ears are covered.
  • My Greatest Failure: Ladybug's plan to corner the Chemist, which resulted in her capturing the Black Cat Miraculous and killing Adrien.
  • Nice Job Breaking It, Hero: Judy keeping Ultrasonic's microphone from Ladybug and throwing it to Nick, who accidentally breaks it, letting the akumatised butterfly get away.
  • No Sympathy: Nick admits to being pissed off by Marinette's behaviour: from his perspective, this is a teenage girl who has gotten herself kicked out of multiple foster homes out of an apparent preference for living under a bridge, despite having no apparent complaints about the homes themselves. When pushed, he explains to Judy about his mother's Sanity Slippage after the incident with the Junior Rangers and how it led to him living on the streets for a while, making the point that Marinette has little to complain about after what the city has tried to do for her.
  • No Time to Explain: Ladybug urging Judy to give her the possessed microphone so she can destroy it and purify the akuma. At this point she has maybe a minute left of her transformation, which indeed is not much time to explain, but it's worth noting she did have an opening earlier, before using her Lucky Charm, when she passed Judy on the way to deal with Ultrasonic. Judy told her it was a job for the police, and Ladybug made little effort to tell her otherwise.
  • Not with the Safety on, You Won't: A variant which overlaps with It Works Better with Bullets. Nick's jailbreak of Marinette is interrupted by an unnamed tiger police officer, who shoots at Nick and narrowly misses. Nick bluffs the tiger by claiming that it's a new model of gun whose safety turns back on automatically when the magazine is emptied. This gives Nick an opening to kick his own tranquiliser gun at the tiger and for the two to get away.
  • N-Word Privileges: Referenced when Marinette starts reminiscing about Chat Noir and his cat puns, and wonders whether they'd be offensive in this world coming from anyone other than a cat.
  • Orphaned Etymology: There's a throwaway reference to "French fries" in one of the later Zootopia chapters. It's only used in the narration, but it stands out considering there are French characters in the story and none of them are in the scene.
  • Outside-Context Problem: Akumas and Miraculous holders to the Zootopians.
  • Police Are Useless: Judy's refusal to cooperate with Ladybug despite her obvious experience with this kind of situation. Less so with Chief Bogo, who at least tries to have Marinette released when he comes to believe her story, and the rest of the cops, while horribly out of their depth, do their best to save civilians from the Ultrasonic army.
  • Pyrrhic Victory: Ladybug and Chat Noir's fight with the Chemist, which ends with the akuma defeated and purified, but the Black Cat Miraculous is lost, Adrien is killed, and Ladybug destroys her Lucky Charm in the process before she can repair any of the damage.
  • Reasonable Authority Figure: Chief Bogo, with his efforts to convince the city Marinette is telling the truth.
  • Recurring Dreams: Marinette's nightmares of Chat Noir's death, which continue to plague her even after a year in Zootopia, though she does sometimes go weeks without them. Combined with a Catapult Nightmare at one point.
  • Sarcasm Mode/Sincerity Mode: Nick manages to combine the two when he apologises to the unconscious Chief Bogo for his role in the jailbreak.
  • Shout-Out: Marinette's feline foster parents are named Luna and Art, no doubt short for Artemis.
  • Teach Him Anger: A variant when Ladybug explains that Clawhauser will have to be akumatised again before she can purify it, which means forcing him to think back to the bitterness about his Z Factor rejection that got him turned the first time. When Marinette first brings this up, Nick states that Clawhauser never gets angry, not really grasping how this works.
  • This Cannot Be!: The Butterfly's reaction after Ladybug defeats Ultrasonic and his army.
  • Took a Level in Jerkass: Marinette, who has been lashing out at Tikki for some time, ever since her search for a way home started getting her in further trouble and Tikki started urging her to let it go and try to rebuild her life here. They manage to reconcile after the first Ultrasonic attack.
  • Trapped in Another World: Marinette and Tikki have wound up in Zootopia, for initially unexplained reasons, though the fact that the Butterfly has somehow followed her there has given them renewed hope of finding a way back. Tikki later suggests that they were brought here by Marinette unconsciously casting Lucky Charm in the catacombs when she was thinking about getting away from Paris, which was just before her timer started running out. As she puts it, "this entire world is one big, souped-up Lucky Charm!" Marinette is justifiably skeptical of this, given that the world is supposed to have had thousands of years of history when she arrived, but she decides that she can't risk the possibility that using her powers to return home would destroy this world.
  • Turn in Your Badge: Nick gets suspended after the first Ultrasonic attack after Chief Bogo finds out from Marinette that he fired a warning shot, violating the first rule of firearm usage: "Shoot to kill, and nothing else."
  • Two Rights Make a Wrong: During the flashback fight against the Chemist, Ladybug manages to separate her from her weapon, a possessed beaker, and she throws her yo-yo at it intending to break it. At the same time, Chat Noir chases after the beaker and would have been able to grab it in time if the yo-yo hadn't hit his hand and caused him to knock it away. As such, the Chemist gets the beaker back and the fight gets drawn out.
  • Unspoken Plan Guarantee: Ladybug's stated plan for Clawhauser is to let him get akumatised again with them present and for her to grab the possessed item as soon as he transforms. It does not go that smoothly.
  • Villainous Breakdown: Even compared to most episodes, The Butterfly does not take the defeat of Ultrasonic well - he's last seen sobbing on his knees after feeding Plagg, and as of the end of the story, seems to have given up on the Ladybug Miraculous.
  • Wacky Marriage Proposal: Downplayed, but the fact that Nick and Judy each bought the other identical engagement rings and intended to propose on the same night would seem to qualify.
  • We Need a Distraction: Mr Big arranges for Precinct One to receive a string of emergency calls from outlying suburbs in quick succession, to empty out the station as much as possible. Chief Bogo starts to suspect something's going on and walks down to the holding cells on a hunch, just in time to get tranquilised.
  • Wham Episode:
    • Chapter 5: Clawhauser gets akumatised after his humiliation on The Z Factor, confirming that the Butterfly has somehow followed Marinette to Zootopia.
    • Chapter 7: In flashback, it's revealed that the Black Cat Miraculous was lost and Adrien was murdered in Ladybug's last fight. Chat's death had previously been hinted at, but the exact circumstances turn this into a Gut Punch, especially compared to the numerous stories out there where Chat sacrifices himself the way he tends to do in the series.
    • Chapter 9: The Ultrasonic attack ends with the butterfly getting away, thanks to Judy's interference.
    • Chapter 10, at least for those not familiar with the Miraculous Ladybug origin episodes: the escaped butterfly multiplies and transforms random citizens into an army of Ultrasonic clones, including Judy, and Marinette is stuck in jail unable to help.

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