Mortimer Mouse

Mortimer Mouse is Mickey Mouse's rival and second arch-enemy in animation, after Pete. Mortimer first appeared in the Mickey short Mickey's Rival and ever since he has been battling Mickey for Minnie's affections.

History
Mortimer's name was originally meant for Mickey Mouse but Walt Disney's wife Lillian thought the name made Mickey seem pompous. Years later, the name would be used for a new character created to be a rival for Mickey. Mortimer only appeared in the cartoon "Mickey's Rival" and was never seen again until 2000 when Mortimer's popularity skyrocketed and landed him roles in several Mickey Mouse related material

Design
Mortimer is essentially a taller version of Mickey Mouse, and seems a bit more human-like. Unlike his rival, Mortimer has whiskers, perhaps referencing how he has a ratlike persona. He has feet the size of Goofy's. Unlike most of the other mouse characters, however, you can see two large teeth close together, like a rat. He is usually wearing jeans and a shirt, but sometimes he also wears a hat

Personality
He is said to be Minnie's ex-boyfriend and she possibly left him due to his nature. He is very arrogant and rude, the total opposite of his rival. While he claims he loves Minnie, he shows to be incredibly selfish as seen in the cartoon "Mickey's Rival" where he leaves Minnie to be attacked by a bull that he provoked. Not only that, he attempts to flirt with any female character on screen which might also indicate the reason the relationship between him and Minnie was abolished. Also, Mortimer can be rather sexist as seen in "Mickey's Rival Returns" where he feels that Minnie is only a prize to be won. It is unkown what he does but as well as being arrogant and sexist he acan also be rather annoying.

Mickey's Once A Upon a Christmas
Mortimer makes a brief appearance in the direct-to-video film Mickey's Once Upon a Christmas. Here, Mortimer is the snooty, profound and wealthy owner of Mortimer's Department Store, and he speaks with a profound tone. Minnie Mouse and Daisy Duck are notable employees of the store, and judging by Minnie's low-budget lifestyle, he does not pay well. In his scene, Minnie hopes to earn the Christmas bonus for her extra hard work, so that she may pay for a wonderful present for Mickey. However, Mortimer only gives her a fruitcake, leaving Minnie without money to buy the gift.

Mickey's Magical Christmas
In  Mickey's Magical Christmas  clips where Mickey went out on the street to ask what people want from Christmas was archive footage from the show but Mortimer's scenes were cut out for unknown reasons. However he is seen two times in the audience but he doesn't talk.

Mickey's Rival
In his first appearance, Mortimer was driving by and notice Mickey and Minnie as they were having a picnic. Minnie is thrilled to see Mortimer once again. As soon as Mortimer walks up, Mickey already knows he is bad news just as Mortimer does not like Mickey at all so he attempts to humiliate Mickey and when Mickey shows Minnie how upset he is Minnie states that he is just jealous. Mortimer then tries to impress Minnie by annoying a bull that is over a fence. The plan works until the bull finds a way out. Mortimer rushes and drives away in his car and leaves Mickey to rescue Minnie who eventually remembers why she left Mortimer in the first place

Mickey Mouse Works
In this series, Mortimer is once again the main antagonist along with Pete. Here, Mortimer is Mickey's neighbor and is still competing with Mickey to win Minnie Mouse's heart. In the series, Mortimer is apparently wealthy having far more advanced technology than his rival. One of Mortimer's most villainous roles was in the cartoon Big House Mickey where he accused Mickey of robbing his house having Mickey sent to prison. Mortimer made a guest appearance in the Pluto segment; Pluto Gets the Paper.

Mortimer's first appearance in the series was the cartoon Mickey's Rival Returns. In this cartoon, Mortimer and Mickey compete with each other in volleyball. The winner gets to ask Minnie on a date. Originally, Mickey refused the idea being that it would be using Minnie as "some kind of trophy", but Mortimer's arrogance angers Mickey into competing. Mickey wins, but Mortimer reveals the competition prize to Minnie having her beleive Mickey thought of her as a prize. Minnie instead leaves with Mortimer but at the date, he begins to harass her for a kiss. Fortunately, she is saved by Mickey who she forgives and has a beach dinner with.

House of Mouse
In the television series House of Mouse, Mortimer gets a role as a recurring character. Mortimer appears many times as a guest and tries to trick Mickey or Minnie into breaking up. In the series pilot episode, Mortimer appears but is seen flirting with Donald Duck's girlfriend Daisy Duck instead. Mortimer proves to be hated by mostly all of the guest at the club ranging from heroes to princesses to villains despite being one himself. It is even indicated in the episode "Pete's Christmas Caper" that the cruel Pete might even have a disliking towards him.

Arguably Mortimer's most famous appearance is where he tricked Mickey and friends into believing he was the club's critic and forced everyone to treat him like a prince or he'll give them a negative review which could close the club. Mortimer is foiled when the real critic reveals himself to be Lumière from  Beauty and the Beast .

Mickey Mouse Clubhouse
Mortimer's most recent appearance is in the CG animated series Mickey Mouse Clubhouse. He has a non-speaking role in Minnie's Birthday seen sitting beneath a tree, playing a guitar. In this appearance, Mortimer wears the orange shirt from Mouse Works with yellow polka dots, blue pants and yellow shoes. He was also seen sleeping and sunbathing on the ground

Trivia

 * Walt was originally going to name Mickey Mortimer, but his wife insisted on a new name. Mrs. Disney felt that the name was not good enough and suggested a name which was more suitable with Walt’s home in Midwestern: Mickey.
 * The name itself derives from the name of Disney's former pet mouse, Mortimer.
 * Mortimer only has one small cameo appearance in Mickey Mouse Clubhouse and was possibly denied a major role due to his nature. He was quiet and was seen under a tree playing the guitar.
 * Although Mortimer hasn’t been used that much in the cartoons, he has been used a lot in the comics particularly the comic from over sea, the most popular ones being Brazil, Italy and France.
 * Mortimer bears resemblance to an obscure character, Ruffhouse Rat, who is a cousin of Minnie's and Mickey had to help train in boxing in one of his earlier comics.
 * In the Berke Breathed strip Bloom County, there is a Mortimer Mouse, who is a stubbly, surly mouse who wears the same outfit as Mickey's, but more disshevled. He is annoyed that he was drafted during the Second World War, during one battle he suffered an injury where a Panzer tank ran over his foot, while at the same time Mickey went on to fame and fortune. This parody was ended after Breathed was threatened with a lawsuit from Disney for unauthorized parod in 1988. Interestingly, Disney had better realtions with Berke Breathed twenty years later when they based a film on his childrens' book Mars Needs Moms.
 * Like Gaston and Chi-Fu, Mortimer has very negative opinions towards women and girls.