Ultimateboy13 goes to Zootopia

Ultimateboy13 goes to Zootopia is first crossover film by Ultimateboy13.

Plot
In a world populated by anthropomorphic mammals, Ultimateboy13 meets a rabbit from rural Bunnyburrow named Judy Hopps who fulfills her childhood dream of becoming the first rabbit police officer in Zootopia, an urban utopia.

Despite being the police academy valedictorian, Judy is relegated to parking duty by Chief Bogo, who doubts her potential. On her first day, Judy and Ultimateboy13 are hustled by Nick Wilde and Finnick, a con artist duo. The next day, Judy and Ultimateboy13 abandons parking duty and arrest Duke Weaselton, a thief who stole plant bulbs.

She is reprimanded by Bogo and nearly fired until Mrs. Otterton arrives pleading for help locating her missing husband – one of many animals recently missing in Zootopia. To Bogo’s dismay, Hopps volunteers and agrees to resign if she cannot solve the case within 48 hours. She sees Wilde in the last known photo of Otterton and tracks him down, coercing him into to assisting her with the investigation.

Judy and Ultimateboy13 discovers that Nick was the last one to see Otterton, so they blackmails him into assisting them by covertly recording his confession to tax evasion. They track Otterton to a limousine owned by crime boss Mr. Big, who reveals that his florist Otterton went "savage" – reverted to a feral state – and attacked his chauffeur Manchas. At his home, Manchas mentions that Otterton had been yelling about "night howlers." Suddenly, Manchas himself goes savage and chases the three. Judy and Ultimateboy13 saves Nick by trapping Manchas and calls the ZPD for help; when Bogo and other police arrive, however, Manchas has vanished. Bogo demands Judy's resignation while still fired, but Nick and Ultimatebo13 defends Judy, pointing out that she still has ten hours to solve the case. As they leave, Nick opens up to Judy and Ultimateboy13, revealing he was bullied as a child for being a fox and subsequently became a con artist, resolving to live out the stereotype of a fox.

Bellwether gives Judy, Nick and Ultimateboy13 access to the city's traffic camera system and they discover Manchas was captured by wolves, which Judy surmises are the "night howlers". They locate Otterton and the other missing predators imprisoned in an asylum where Mayor Lionheart has been keeping them hidden and trying to determine the cause of their strange behavior. Lionheart is arrested and Bellwether becomes the new mayor. Judy, and Ultimateboy13 praised for cracking the case, Ultimateboy13 decides to stay with Nick and Judy so they can on adventures. Judy asks Nick and Ultimateboy13 to join the ZPD and become her partner, which hNick and Ultimateboy13 happily considers. However, Judy then speaks at a press conference and unintentionally upsets Nick by suggesting a biological cause for the recent predator behavior. Nick refuses her offer and angrily leaves, and a guilt-ridden Judy quits her job amid a wave of fear and protests against predators, a minority group.

Back in Bunnyburrow, Judy and Ultimateboy13 learns from Judy's parents and reformed childhood bully Gideon Grey that "night howlers" are toxic flowers that have severe psychotropic effects on mammals. Judy and Ultimateboy13 returns to Zootopia and reconciles with Nick. They find Weaselton and discover that the bulbs he was stealing were night howlers intended for a ram named Doug. Locating Doug at a lab hidden in the subway tunnels, they find him creating a night howler serum which he has been injecting into predators via a dart gun.

Before they can bring the evidence to the ZPD, Bellwether intercepts them and steals it, revealing herself as the mastermind behind a prey-supremacist conspiracy. Judy, Nick and Ultimateboy13 are trapped in a pit by Bellwether's henchrams after Nick and Ultimateboy13 refuses to abandon Judy when she is injured. Bellwether calls the police, intending to use the serum to make Nick kill Judy, but Nick and Ultimateboy13 has disarmed the weapon by replacing the serum pellets with blueberries, and Judy has recorded Bellwether's confession. The police arrive and arrest Bellwether.

Lionheart denies any knowledge of Bellwether's plot, but asserts that he imprisoned the savage predators for the "right reasons." Judy rejoins the ZPD, and Nick, along with Ultimateboy13 joins to become her partner and the first fox police officer. The savage predators are cured by an antidote. During the film's closing credits, popstar Gazelle holds a concert to celebrate with Bellwether and her accomplices angrily watching in prison.