Ken Anderson drew many different designs for Medusa, including a Lauren Bacall-esque "grande dame" (with snake-like locks of hair, true to her name), a vain, sinister, slender lady and a portly woman with a facade of make-up, in an attempt to find the right personality. The design eventually settled on a rather hideous appearance (of which she seemingly remains unaware), with an excess of makeup, sagging breasts, green eyes and wild, fiery red hair to suit her fiery personality.
For a small amount of time early in the film's production, the Disney story team was heavily considering reusing Cruella De Vil from their 1961 classic, One Hundred and One Dalmatians. Drawings by Ken Anderson depicted her in alligator skins, suggesting that she would have visited, or had dealings with, Devil's Bayou. (John Canemaker, "Before the Animation Begins: The Life and Times of Disney inspirational Sketch Artists") This idea was abandoned, as the studio was not interested in producing sequels at the time, and Madame Medusa was created. Cruella and Medusa share certain characteristics, including fixation on a single goal, a fiery temper, vanity and a tendency to drive recklessly.
Medusa is loosely based on the Diamond Duchess, an elderly woman who served as the villain in Margery Sharp's original novel, Miss Bianca, and who similarly wanted to obtain a specific diamond and was using an orphan girl in her plan (named Patience in Sharp's novel). However, Medusa has a somewhat wilder, more eccentric personality than the Diamond Duchess.
In addition to inheriting some traits from Cruella, Medusa may well have passed on of her traits on to Ursula, including a similar appearance, and the possession of 2 scaly green pets (Brutus and Nero for Medusa; the Moray Eels, Flotsam and Jetsam for Ursula).
Medusa's name most likely comes from the Greek mythological monster of the same name. The monster had snakes for hair; the Disney character has normal red hair, which nonetheless looks rather snaky. Whenever the Rescuers character stares at Penny, the girl freezes temporarily; whoever looked the Greek monster in the eye would turn to stone.
Medusa is described as a greedy and obsessed person. She is completely fixated on diamonds; when we first see her pawn shop, there is a prominent sign advertising half rates for people who bring in diamonds, and though she could have made a lot of money on the assorted pirate treasure in the cave, she brushes it off because the world's biggest diamond is the only thing she's after. She is also very crazy, ill-tempered, and sometimes unstable, which makes her intimidating at times. However, she has a bit of a bumbling nature, which makes a little hard for people to take her seriously as a really scary villain. She is very intelligent and patient, but when she comes to the point of losing it, she is not someone you want to be around. She will stop at nothing to get what she wants; such as using Penny, a little girl, to go down into a dark cave just to retrieve the Devil's Eye.
Prior to the film, Medusa discovers that the world's largest diamond, the Devil's Eye, is buried deep underground in a pirate's cave in Devil's Bayou. Much to her disappointment, the cave entrance is much too narrow for her to fit through. Neither her incompetent henchman, Mr. Snoops, nor her two pet crocodiles, Brutus and Nero, can fit through it. It is then that she decides to return to New York, where her pawn shop is located, and captures the poor orphan Penny to fetch the diamond for her.
Three months later (when the film introduces her), Medusa finds that although Snoops has managed to force Penny down into the cave, he is unable to persuade her to search. Moreover, he has caught the little girl sending out messages in bottles. Medusa, frustrated with Mr. Snoops' inability to manage an orphan girl, takes the next flight back to Devil's Bayou to take charge.
Upon arriving, Medusa made things even more miserable for Penny, so much so that Penny attempted to run away numerous times, only to be caught by Medusa and her two faithful crocodiles every time. Medusa lost her patience with Penny and declared that no matter what, Penny would find the Devil's Eye, and would stay underground until she did so, regardless of the danger. Prior to their search, Bernard and Miss Bianca from the Rescue Aid Society in New York arrive to try to save Penny, but Medusa panics upon the sight of them and nearly blows them away with her shotgun. This fails however, as the two mice escape and soon afterwards meet Penny face-to-face.
She ultimately forces Penny down into the cave, holding her teddy bear hostage, and refusing to lift her back out until she has found and retrieved the diamond. Since the cave fills with water at each high tide, Penny was aware that Medusa's threat was a potentially lethal one. She was accompanied by Bernard and Miss Bianca and with their help, she found the Devil's Eye. Unfortunately, it was stuck in the skull of a dead pirate and they could not get it out, but Medusa refused to hoist Penny up until she retrieved it. With the tide rising and the waters splashing violently, Penny and the mice recovered the diamond by opening the skull with a sword, and were lifted back to the surface just in time. Medusa immediately indulged in her newfound wealth, refusing to let Snoops so much as look at it. The group made their way to the riverboat where Medusa planned her escape.
While Miss Bianca and Bernard called their swamp friends for help, Medusa held Penny and Snoops at gunpoint, intending to escape with the diamond herself (Which she hid in Penny's teddy bear). However, the two mice literally trip Medusa up, allowing Penny to grab the diamond and make a run for it. Medusa and her crocodiles fought the animals slowing her down but was easily overpowered, and was soon at the mercy of Mr. Snoops' fireworks after the animals set them off.
Penny fled in Medusa's swampmobile, but Medusa refused to give up, and pursued Penny by water skiing. She ran into her two crocodiles and whipped them with a rope to get them to move faster, much to their anger. However, the ropes broke and Penny was able to escape and Medusa was sent flying into her riverboat, which was now sinking due to the fireworks display. Medusa watched in defeat as Penny and the animals escaped with the Devil's Eye, leaving her to face the angry Brutus and Nero alone while Mr. Snoops fled the scene, all the while laughing at Medusa's misfortune.
It is unknown if Medusa was able to escape the angry crocodiles, although it's implied that she never escaped in time and was presumably killed by them.
Medusa made a few cameos in the animated series and was seen in a crowd shot in Mickey's House of Villains. However, she was not one of the villains to join in the hostile takeover.
- Medusa is one of the 10 villains featured in the tongue-in-cheek Disney Villains: The Top Secret Files. Medusa's section of the book includes a photo of Nero and Brutus as babies, and a catalog of the world's greatest diamonds (most of which Medusa has scrawled 'too small!' over). Medusa is ranked as the ninth greatest Disney Villain at the end of the book.
- It has been noted that Madame Medusa and Ursula share a similar facial structure.
- Actress Geraldine Page who provided the voice of Madame Medusa was married to the actor Rip Torn. In 1997, 10 years after Page's death of a heart attack, Rip Torn provided the voice of Zeus in Disney's Hercules.
- Both Medusa and McLeach end up being chased by crocodiles.
- Disney based Medusa on The Duchess of Diamonds from Margery Sharp's novel.
- The car Medusa speeds away in is very similar to Cruella De Vil's.
- Medusa is one of the few green-eyed redheads in the Disney universe.
- Madame Medusa was named after the Greek mythological creature, Medusa, which had the power to turn anyone or anything, who looks into her eyes, into stone and was later defeated by Perseus.
- The role of the antagonist in The Rescuers was going to go to Cruella De Vil, but went to Medusa instead. Despite this, Medusa does share similarities to Cruella de Vil.
- Both drive very recklessly, though seem to believe they are not.
- Both wear sleeveless dresses.
- Both are thin.
- Both are fine with hurting the innocent (Medusa: Penny; Cruella; Dalmation Puppies) in order to achieve their ends.
- Both have old phones, though this may be due to the time period.
- Both have unintelligent sidekicks (Madame Medusa: Mr. Snoops; Cruella: Jasper and Horace Badun).
- Both appear to be very rich.
- Both appear to hate animals (in Madame Medusa's case, mice; in Cruella's case, dogs).
- Both got stranded as a defeat and got back at by their henchmen (Mr. Snoops laughed at Medusa, and Jasper and Horace told Cruella to shut up. Cruella was stranded in the English countryside due to her damaged car, and Medusa was stranded on the boat chimney unable to escape Brutus and Nero. But Madame Medusa didn't return for the sequel whereas Cruella returned where she got arrested as her defeat.
- Both have bad tempers.
- Both were seen slamming their telephones, due to frustrating talks with their henchmen.
- Both sobbed about losing what they wanted when defeated (Medusa: The Devil's Eye, Cruella: Dalmatian Puppies).
- Both have red cars.
- Both chased the deuteragonist (Medusa, Penny; Cruella, Perdita).
- Madame Medusa shares some similarities to Lady Tremaine from Cinderella.
- Both have girls they keep for selfish reasons. Lady Tremaine has her stepdaughter Cinderella for chores, while Madame Medusa uses Penny to retrieve the Devil's Eye diamond from the Black Hole.
- Both are psychologically abusive towards their unfortunate girls.
- Both have beloved pets (Lucifer the Cat, Brutus and Nero the crocodiles).
- Both are outwitted by mice duos. (Jaq and Gus, Bernard and Bianca).
- Medusa is similar to Captain Hook as both are the main antagonist, slender, have unintelligent sidekicks (Madame Medusa: Mr. Snoops; Hook: Mr. Smee), kidnap young children Madame Medusa: Penny; (Hook: Tiger Lily, Wendy Darling, her brothers and the Lost Boys) and prey for crocodiles.
- She is also similar to Bill Sykes. They live in New York. Also, they are both the main antagonist, impatient, kidnap young girls (Medusa: Penny, Sykes: Jenny Foxworth) for greedy reasons (Medusa for the Devil's Eye and Sykes for money), both have male pets that look alike (Brutus and Nero for Medusa, Roscoe and DeSoto for Sykes), and both would do anything to get their way. In the climax, they chase the animals that saved the ones that they kidnapped (in Medusa's case, Bernard, Miss Bianca, Ellie Mae, and the swamp folks; in Sykes' case, Oliver, Dodger, and the gang).
- Madame Medusa shares some similarities to Ursula from The Little Mermaid.
- Both appear hideous, yet wear revealing outfits.
- Both kidnap girls for selfish reasons. Ursula plots to use Ariel against her father King Triton and obtain his Trident and throne, while Madame Medusa uses Penny to retrieve the Devil's Eye diamond from the Black Hole.
- Both have performed makeup in the girls' presence.
- Both have performed a sloppy waist-shaking dance.
- Both have beloved pets (Flotsam and Jetsam, Brutus and Nero the crocodiles).
- Both are outwitted by animal duos. (Scuttle and Max, Bernard and Bianca).
- She is very similar to her successor, Percival C. McLeach from The Rescuers Down Under. They are both the main antagonists and slender. She kidnapped a young girl in order to find a precious diamond, while he kidnapped a young boy in order to find the Golden Eagle. They both own reptiles as she owns two male crocodiles, Brutus and Nero, while he owns a female goanna, Joanna, though Joanna was more like Mr. Snoops from the first film as they are both the secondary antagonists. They both have shotguns. Although, she's less intelligent and evil as she never attempted to kill Penny, while he is willing to kill Cody after he caught Marahute to keep him from being arrested. She just wanted to make off with the diamond and leave Mr. Snoops and Penny on Devil's Bayou, stealing Penny's teddy bear in the process. He is also a slightly superior shot than her, though probably only because his gun has a scope. However, she was ranked as the #16 Disney villain, but he has not been ranked although fans feel he should have been, especially when McLeach was given the traditional Disney Villains' Death, while Madame Medusa did not.
- Medusa suffers a similar fate to Scar. Both villains betray their minions causing them to turn against them (Madame Medusa refuses to let Mr. Snoops have the Devil's Eye and leaves him on Devil's Bayou and whips at Brutus and Nero and Scar pins Mufasa's death on the hyenas) but it is unclear if Medusa, like Scar, was killed.
- Madame Medusa shares some similarities to Mother Gothel from Tangled.
- Both kidnap girls for selfish reasons. Mother Gothel kidnap Rapunzel for her healing hair, while Madame Medusa uses Penny to retrieve the Devil's Eye diamond from the Black Hole.
- Both are psychologically abusive towards their unfortunate girls.
- Madame Medusa is very similar to the 1939 film 'The Wizard of Oz's villain The Wicked Witch of the West as the pair serve as their respective film's main antagonist, kidnap the leading ladies (Penny in Medusa's case and Dorothy Gale in the Witch's case), are after something badly (Medusa wanted the Devil's Eye and the Witch wanted the ruby slippers), both have animal minions (Medusa's crocodiles and the flying monkeys respectively), are ugly in appearance and hold something deemed precious to the girls (Medusa had hold of Teddy to hide the diamond while the Witch and her Kansas counterpart Miss Gulch had hold of Toto, Dorothy's dog).