Judge doom is the main villian of the film,Who framed roger rabbit which is what toontown is based of off.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" (the Pacific Electric Railway) for the sole purpose of putting it out of commission. He then orders Jessica and Roger 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, Judge Doom is run over by a steamroller, but 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 he reinflates with an oxygen tank, he shows his red toon eyes and talks in a high squeaky voice and Eddie recognizes Doom as the bank robber in Toontown long ago who murdered his brother, Teddy Valiant, thus triggering his hatred towards Toons and explaining how Doom managed to buy the judicial election and the trolley car company.
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. Doom 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, and decide to live happily ever after when Marvin Acme's will suddenly appears in Roger's possession, granting full ownership to the citizens of Toontown.
Despite being a main part of the movie toontown is based on,he is not mentioned much by fans.