Mortimer Mouse is a character created by the Walt Disney Company. He is a tall anthropomorphic rodent who is Mickey's rival, often for Minnie's affections. The character originated as Mr. Slicker in the Mickey Mouse comic strip storyline "Mr. Slicker and the Egg Robbers" in 1930 before making his animated debut in the 1936 cartoon Mickey's Rival. His name is a reference to the fact that Mickey himself was originally going to be named Mortimer, but his name was changed to Mickey after Lillian Disney (Walt Disney's wife) pointed out that the name Mortimer sounded "too pompous". Although Mickey's Rival would mark Mortimer's only appearance in the original shorts, he continued to regularly antagonize Mickey in comic book stories (where he was sometimes called Montmorency Rodent), and eventually returned to animation on Mickey Mouse Works. Mortimer is not to be confused with Minnie's rich uncle who has the same name, or Mickey's nephew Morty Fieldmouse.
Appearances in Christmas specials
Mortimer's first appearance in a Christmas production was a brief appearance in the 1999 direct-to-video film Mickey's Once Upon a Christmas. Here, he is the wealthy owner of a department store where Minnie and Daisy work as his employees. In the one scene Mortimer appears in, Minnie is hoping to receive a nice Christmas bonus for her hard work so that she can buy a great Christmas present for Mickey. Unfortunately, all Mortimer gives her is a fruitcake, leaving poor Minnie with no money to buy Mickey's present. It should be noted that Mortimer's character is slightly different here than his usual appearances; he does not have his usual buck teeth and is drawn with a mustache instead of whiskers, and also has a much snootier personality than normal.
The Mickey Mouse Works short "Mickey's Christmas Chaos" marks Mortimer's most prominent role in a Christmas special. Here, he is competing against Mickey in Main Street's annual Christmas decorating contest, which he has beaten Mickey in at least once before. Throughout the short, Mortimer continually outdoes Mickey in decorating his house and vice-versa. By the end of the short, Mortimer and Mickey end up blowing up both their houses, and Pluto's doghouse wins first prize in the contest.
Mortimer also appeared in both of the House of Mouse Christmas episodes, "Pete's Christmas Caper" and "Clarabelle's Christmas List". As a running gag in both episodes, he continually tries to get Minnie to kiss him under the mistletoe, which always backfires because he is either actually holding something different over his head or he ends up getting kissed by someone else. Also, in a segment featured in "Pete's Christmas Caper", in which Mickey goes about asking other Disney characters what they want for Christmas, Mortimer is shown asking for Minnie and Daisy's phone numbers, after which he gets beaten up offscreen and then asks for a doctor's phone number. Mortimer also made a brief cameo in the audience at the beginning of Mickey's Magical Christmas: Snowed in at the House of Mouse.