Dexter's Laboratory: Last Experiment

Dexter's Laboratory: Last Experiment is an upcoming 2025 hand-drawn animated science-fiction comedy film based on the Cartoon Network animated television series Dexter's Laboratory created by Genndy Tartakovsky. The film will be directed by Tartakovsky from a screenplay by Amos Vernon, Nunzio Randazzo, and Tartakovsky and a story by Tartakovsky and produced by Marc Platt, Jerry Bruckheimer, and Christopher DeFaria. All the voice actors except Eddie Deezen reprise their roles from the series, with Will Forte voicing 18-year-old Dexter, Candi Milo reprising her role as young Dexter in the film's opening scene, and Nick Kroll becoming the new voice of Mandark.

The film serves as the fourth installment of the Cartoon Network Cinematic Universe (CNCU) and the epilogue of the series. The film follows eighteen-year-old Dexter as he and his family team up with Monkey and Agent Honeydew to save the world from Mandark.

This film is dedicated to the loving memory of Christine Cavanaugh, who voiced Dexter in the first two seasons and Ego Trip.

Produced by Warner Animation Group and Cartoon Network Studios, the film is scheduled to be released in theaters on June 20, 2025, by Warner Bros. Pictures.

Synopsis
The story takes place ten years after the original series. Dexter is now an 18-year-old young adult scientist preparing to go to college. However, his older sister, Dee Dee, asks him to tell their parents about the laboratory, which he kept a secret from them for a long time. While working on his last experiment before leaving for college and because he has to tell his parents about his laboratory, Dexter develops an incestuous romantic relationship with Dee Dee and, to a lesser extent, their mother. Meanwhile, Dexter's longtime nemesis, Mandark, has unleashed his evil plot for world domination. So, Dexter and his family must team up with Monkey and his wife, Agent Honeydew, to stop Mandark for good.

Plot
On a school morning, Mary Spencer O'Reilly-McPherson asks her daughter, Dee Dee, to go and see if her younger brother, boy genius Dexter Michael Louis McPherson III, is ready to go to school. Dee Dee readily agrees to this and dances to Dexter's room door. After knocking, there is no response, and the door is locked. Dee Dee then uses an express credit card to break the lock and enter Dexter's room. She races into Dexter's laboratory and finds him working on his new invention, a remote that turns people into animals.

Dee Dee causes chaos, and Dexter tries to stop her, but she uses the remote to turn him into various animals. A fight ensues as they turn each other into various animals. Soon, they end up turning into a snail and a turtle. In the end, they become human again, but they switch bodies. After school, Dexter and Dee Dee return to his laboratory and use the remote one last time. Soon, they're back in their own bodies and vow to never mess around with the remote again. They leave the lab afterwards.

Ten years later, Dexter turns 18, and he and his family are preparing for his departure to college. Dexter is excited to move on to college and start a new life. As he is packing, his older sister, Dee Dee, discovers his secret laboratory and asks him to tell their parents about it before he leaves. Dexter has been keeping his lab a secret for years. Dee Dee also reveals that she has feelings for him. Dexter is hesitant and unsure of how to go about it. So, Dee Dee suggests that he use his science skills to make something that will convince their parents. Dexter reluctantly agrees and starts working on his latest invention.

At the same time, Dexter's longtime nemesis, Susan "Mandark" Astronomanov, is planning his world domination scheme. He has created an army of robots and is ready to launch his plan. Dexter uses his knowledge to create a robotic duplicate of himself that he can use to tell his parents about the laboratory. When he's finished, he shows it to Dee Dee. But when she turns on the robot, it malfunctions and starts to pursue her, much to her horror. As the robot chases her around, it destroys most of the lab. Dexter rescues Dee Dee and turns off the robot before it can damage the lab any further. Then, he repairs and reprograms it to make sure it doesn't harm anyone or damage anything again, much to Dee Dee's relief.

Meanwhile, Mandark's plan is almost complete. He is about to launch a laser satellite weapon so he can use it to take over Genius Grove, then Townsville, and then the world. Desperate to stop Mandark, Dexter and his family team up with Monkey and his wife, Agent Honeydew, to break into Mandark's lair and foil his evil plans. Dexter and Dee Dee's romance continues to grow, but they face obstacles as their parents are completely against the idea. Meanwhile, Mandark's robot army continues to cause destruction and chaos.

Dexter and his team begin their mission to foil Mandark's evil plan. However, despite their best efforts, they fail to stop it. Mandark's plan for world domination succeeds, and the world is plunged into chaos. To save it, Dexter must find a way to reverse Mandark's plan. He discovers that he can use his scientific knowledge to reprogram the robots and restore order. After much struggle and with the help of Monkey and Agent Honeydew, Dexter and his family are able to defeat Mandark and save the world.

In the aftermath, Dexter and Dee Dee's relationship has grown stronger, and their parents finally accept it. They also learn about Dexter's laboratory and accept him as the boy genius they know and love, much to his delight. Dexter returns the favor by starting a romantic relationship with his mother. With the world saved, Dexter and Dee Dee decide to stay together as they're free to start their new life in college.

Cast

 * Will Forte as Dexter Michael Louis McPherson III, an 18-year-old young adult scientist who works at his secret laboratory beneath his house. He's the film's main protagonist.
 * Candi Milo as young Dexter
 * Kat Cressida as Dee Dee McPherson, Dexter's 20-year-old sister. She serves as Dexter's primary love interest.
 * Nick Kroll as Susan "Mandark" Astronomanov, Dexter's longtime nemesis. He's the film's main antagonist.
 * Kath Soucie as Mary Spencer O'Reilly-McPherson, Dexter's mother. She serves as Dexter's secondary love interest.
 * Soucie also voices Agent Honeydew, Monkey's wife.
 * Jeff Bennett as Hugh McPherson, Dexter's father.
 * Johnny Depp as Monkey, Dexter's pet lab monkey and Agent Honeydew's husband.
 * Frank Welker provides his vocal effects.

Development
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Music
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