The Thugs are supporting antagonists from Disney's 26th full-length animated feature film The Great Mouse Detective, which is based on the children's book series Basil of Baker Street by the late Eve Titus and the late Paul Galdone. They are Professor Ratigan's henchmen.
The thugs are helping out with their boss' plan to overthrow the Queen and become ruler and guards of Mousedom. They also tend to despise Ratigan's nemesis Basil of Baker Street due to his numerous foiling of Ratigan's previous plots. During the song "The World's Greatest Criminal Mind", one of the thugs (named Bartholomew) accidentally calls Ratigan a rat, and Ratigan has him fed to his cat named Felicia, while three of the thugs watched sadly and mourned for the loss of Bartholomew before continuing on with the musical number.
As part of the plan, Ratigan's second-in-command Fidget steals tools, gears and uniforms for the gang to use, as well as kidnapping the local toymaker Hiram Flaversham to create a robot version of the queen. Fidget also kidnaps his daughter Olivia to ensure that Hiram will cooperate with Ratigan's plan.
Later on, when Basil and Dawson (disguised as sailors) sneak into the lair, Fidget dresses up as Olivia to lure them into a surprise trap set up by Ratigan and his men. As such, the thugs happily taunt Basil for falling into Ratigan's trap, causing him to enter into a depression.
Ratigan then orders his thugs to tie Basil and Dawson in a mousetrap. They all leave for Buckingham Palace dressed in the guard uniforms that Fidget stole for them. At the palace, the thugs manage to ambush the real guards and enter the Queen's room, delivering her a present (which happens to be the robot queen toy). Ratigan appears and orders Fidget to take the Queen away while ordering the thugs to take their places. The thugs then stand on guard during the robot queen's speech, during which, it announces Ratigan as her new royal consort, much to everyone's shock. The lizard thug manages to give notes for Hiram at gunpoint to read into the robot Queen's speaker voice to say to the crowd.
Luckily, Basil, Dawson, and Olivia manage to escape the trap and manage to arrive at the palace, where they save both Hiram and the Queen and fight off Ratigan and his thugs with the help of the crowd. The thugs are eventually captured and tied up by the crowd, but Ratigan escaped with Fidget on a dirigible. It is unknown what has happened to the thugs following Ratigan's defeat, though it is implied that they are arrested for their crimes.
The thugs may actually be terrorists, as they help Ratigan commit political-based crimes, such as the attempted usurpation of Queen Mousetoria.
One of Professor Ratigan's thugs is Bill the Lizard from Disney's 1951 animated film Alice in Wonderland.
The lizard thug is also the only animal in the film who is not a mammal; instead a reptile.
It is unclear how Queen Mousetoria and the crowd did not recognize the Thugs in uniforms are not real Royal Guards, since the English army of that time (end of XIX century up to 1916), all members of the British army had to have a mustache and not one of the Thugs had it. That said, it's possible that the movie producers didn't count that option or that the rodent community doesn't have these requirements.
Despite being Ratigan's minions, they are not the secondary antagonists, Fidget is, as the latter is Ratigan's main henchman; the thugs serve as his lesser henchmen.