Padriac Ratigan is the main antagonist of The Great Mouse Detective.
Ratigan is responsible for such crimes as the Big Ben Caper and the Tower Bridge Job. A genius criminal mastermind whose ego is matched only by his lust for power, Ratigan's latest insane plan is to kidnap a toymaker, force him to make a robotic duplicate of the queen, and use it to publicly proclaim him king in her place. Only one thing stands in Ratigan's way: "That miserable, second-rate detective, Basil of Baker Street." Ratigan lives in a secret underground hideout where he has countless henchmen sing his praises, light his cigarettes, and cater to his every evil whim. At the end of the movie, Ratigan finally snaps out in extreme anger, and he shreds his clothing, extends his apparently retractable claws through his gloves, and attempts to kill Basil, slashing at him in an uncontrollable rage, any pretenses of mouse civilization abandoned. The battle ends with Ratigan falling off of Big Ben.Although he is a rat, he hates being called one (preferring the description of a "big mouse") as rats have a reputation of being base, dirty creatures. To eliminate any possible signs of lower breeding, he presents himself as a sophisticated dandy, sporting a full black tuxedo suit with a orange and purple cravat, white dress shirt with collar, dark gray tuxedo vest, black suit pants, white gloves (like the kind worn by Mickey Mouse), a black and red cape (similar to Count Dracula's) and a gold cigar holder. He also has pet cat named Felicia, whom he adores, and therefore he treats with love and respect since Felicia is loyal to him. Like all the greatest villains, Ratigan has a taste for the theatrical and has a tendency for throwing himself into melodramatic poses and giving lengthy and verbose speeches. Despite this, he is prone to explosive bouts of violence, after which he must switch back to his dandified persona. Two examples would be feeding a drunk mouse named Bartholomew to his cat (named Felicia) for calling him "the world's greatest rat", and fatally tossing his lead henchman (a peg-legged bat with a crippled wing) off the side of his personal zeppelin to "lighten the load". He is also notable for being the only character played by Vincent Price to have said actor sing. Ratigan was based on Sherlock Holmes' archenemy, Professor Moriarty. He appeared in an episode of House of Mouse (voiced by Maurice LaMarche) when he set a trap for Basil, who thwarted it. He ranked #17 in the Top 30 Disney Villains (One better than Shan Yu but one under Madame Medusa).
Ratigan believes he is superior to everyone around him and as such, he expects the rest of the world to act as a chorus that sings his praises. He loves every minute of being evil, gloating, "Oh, I love it when I'm nasty." In addition he has no scruples whatsoever, threatening women, children, old men and even royalty and taking a remorseless pride in his actions. Despite his vicious nature, Ratigan presents himself as a cultured and elegant dandy, but this is only a facade to hide the raging, insane monster within. His henchmen are scared of him for this reason and do their best to please him or experience his wrath. Ratigan's vanity is shown by his pretense at being "a big mouse" when in fact he is a sewer rat. It could be that his insatiable ambition and his expensive tastes are as a result of trying to distance himself from his undesirable background.
- Ratigan was the first Disney villain to sing his own song since Kaa in 1967.
- He made a cameo appearance in House of Mouse with Basil and Dr. Dawson when he made a trap for them. He was voiced by Maurice LaMarche.
- Ratigan shares a few similarities with Cruella de Vil from 101 Dalmatians. Both of their films involve the male (and only) protagonist (Basil in Ratigan's case, Pongo in Cruella's case) and the deurtagonist same to their gender (Dr. David Q. Dawson in Ratigan's case, Perdita in Cruella's case) with help from a dog (Toby for Basil and Dawson, Colonel for Pongo and Perdita). They both are the main antagonist, live in England, smoke cigarette poles, intimidate their henchmen (Ratigan: Fidget and Bartholomew, Cruella: Jasper and Horace Badun), smash the doors real hard, develop red eyes in the climaxes while chasing the protagonist, and gradually reveal their true personalities: utterly violent and insane. However, Ratigan is a male while Cruella is a female.
- Ratigan also shares a few traits with Gaston. They both sing songs that praise themselves with their minions joining along, threaten to hurt someone if they don't get what they want, reveal their true natures as violent and insane, fight the protagonists on a high area, and fall to their deaths and are not seen again. A major difference between them, however, is that Ratigan's minions obviously fear him (only continuing with their praising song for Ratigan when he gave the implied threat of feeding them to his cat Felicia if they didn't), while Gaston's minions do not fear him at all.
- Ratigan is very similar to Mortimer Mouse from Mickey Mouse and friends franchise. Both are villainous rodents, who always like to torment mice protagonist (Basil the Baker Street and Mickey Mouse). The happening of their torment was on 20th June (Ratigan's case: 1897, Mortimer Mouse's case: 1936 (due to release date and year)). They both appeared with the year ---6 (Ratigan's case: 1986, Mortimer Mouse's case: 1936). For their defeat, Ratigan has been fallen down, whilst Mortimer Mouse has been thrown over by his archrival.
- Ratigian's songs, "The World's Greatest Criminal Mind" and "Goodbye So Soon" were written specifically for Vincent Price so he could as campy and over-the-top as possible.