When the film first introduces Doom, Lt. Santino confides to Eddie that Doom bought the election. Later, at the Terminal Bar, Doom uses the "shave and a haircut" trick to lure Roger out, then prepares to execute him. After a brief scuffle inside the bar, he orders the weasels to capture Roger and Eddie. Roger realizes he's in trouble with Doom after him and begs Eddie to hide him. When Eddie learns that studio head R.K. Maroon is connected to the plot to frame Roger, Eddie interrogates him, but Maroon pleads that he is "a dead man" if he confesses. Just as Maroon is about to spill everything, he is killed by an unseen gunman who nearly shoots Eddie as well.
Upon chasing the killer to Toontown, Eddie catches Jessica, thinking she's the murderer, but Jessica reveals that Doom was the one who killed Acme and Maroon. At the film's climax, he traps Eddie, Roger and Jessica in the Acme Factory to explain his scheme: erase Toontown from the map using a giant, mobile vat of Dip linked to a high-pressure water cannon and then build a freeway over it. He then plans to retire from being a judge and control all the profits from the new road system. Doom also reveals that he is the sole stockholder of Cloverleaf Industries and explains that he bought the "Red Car Trolley" (the Pacific Electric Railway) for the sole purpose of putting it out of commission. He then orders Roger and Jessica to be tied up and raised into the air via a skyhook to be sprayed by the Dip cannon.
Eddie distracts the Toon Patrol using hilarious antics (partly while singing The Merry-Go-Round Broke Down to the accompaniment of a music machine playing the tune) to make them literally laugh themselves to death, then attempts to rescue Roger and Jessica when he is interrupted by Doom. The two men then square off, dueling with various ACME props. During the fight, Doom is run over by a steamroller, but he does not die as expected.
As the steamroller crushes him, Doom's body is flattened into a flimsy paper-thin shape, revealing himself to be a Toon wearing an assortment of fake, but live, props, such as fake eyeballs, false teeth, and a rubber mask in order to disguise his Toon body. After Doom re-inflates himself with a helium tank, he reveals himself, much to Eddie's horror, as the same Toon who murdered Eddie's brother, Teddy Valiant, thus triggering his hatred towards Toons and explaining how Doom managed to buy the judicial election and the trolley car company. His voice grew higher until it reaches a horrifyingly high pitch and his eyes turn to daggers, showing Doom's intent that he is now out to kill him, as well.Being a Toon, Doom turns out to be capable of sprouting an anvil and an extendable buzz saw from his hand, with which he attempts to kill Eddie. In the end, Eddie proves to be too clever, using his own concoction to melt him, leaving behind his human disguise. He melts away screaming "I'm melting! Melting!" before he dies. A crowd of various Toons then surround his burned empty suit and melted face and wonder what kind of Toon he was. It hasn't been revealed what type of Toon he was or if he was one specific type of Toon at all, but the Toons seem to agree that they don't need to know.
Graphic novel versionEdit
In the graphic novel Roger Rabbit: The Resurrection of Doom, it is explained that Doom was originally a Toon named Baron von Rotten, who took up the role of playing the antagonist in movies, until an accident in which Von Rotten suffers a concussion, and awakens believing he is a real villain. Von Rotten thus begins his crime career, robbing the First National Bank of Toontown, then killing Theodore 'Teddy' Valiant by dropping a piano on his head, and spreading the stolen money all over the town in order to buy the election for Judge of Toontown, assuming the new name of Judge Doom.
Powers and abilitiesEdit
In his human guise, Doom uses his skull-headed swordstick and ACME products tries to fight Valiant. While in his toon form, he has evil red eyes and a squeaky voice, and is able to produce an arsenal of tools from his body which he can employ as weapons, including a buzzsaw and an anvil. He can't jump far distances, and (like most toons) can survive anything but his own dip, which dissolves him to his death.
- When he dissolves in dip, Doom screams the line originally quoted by the Wicked Witch of the West in the Metro-Goldwyn-Mayer 1939 film, "The Wizard of Oz".
- Doom is one of four male villains to shapeshift into a second form, the others being Jafar, Oogie Boogie, and Turbo. He is also technically the first male villain to shapeshift, although some would argue that his Toon-Form already existed, making Oogie and Jafar the only male shapeshifters. The same deal goes with Turbo.
- In a deleted scene, it is revealed that Judge Doom is Man from Bambi, but this was cut for unknown reasons.