Oswald the Lucky Rabbit in the context of "Animated series"

Mickey Mouse is a cartoon character co-created in 1928 by Walt Disney and Ub Iwerks. The longtime icon and mascot of the Walt Disney Company, Mickey is an anthropomorphic mouse who typically wears red shorts, large shoes, and white gloves. He is often depicted with a cast of characters including his girlfriend Minnie Mouse, his pet dog Pluto, his best friends Donald Duck and Goofy, and his nemesis Pete.

Mickey was created as a replacement for a prior Disney character, Oswald the Lucky Rabbit. The character was originally to be named "Mortimer Mouse", until Disney's wife, Lillian, suggested "Mickey". Mickey first appeared in two 1928 shorts Plane Crazy and The Gallopin' Gaucho (which were not picked up for distribution) before his public debut in Steamboat Willie (1928). The character went on to appear in over 130 films, mostly shorts as well as features such as Fantasia (1940). Since 1930, Mickey has been featured extensively in comic strips (including the Mickey Mouse comic strip, which ran for 45 years) and comic books (such as Mickey Mouse). The character has also been featured in television series such as The Mickey Mouse Club (1955–1996).

Ubbe Ert "Ub" Iwerks (/ʌb ˈaɪwɜːrks/ ub EYE-wurks; March 24, 1901 – July 7, 1971), was an American animator, cartoonist, character designer, inventor, and special effects technician. He was known for his early work with Walt Disney, especially for having worked on the creation of Mickey Mouse and Oswald the Lucky Rabbit, among other characters.

Iwerks and Disney met in 1919 while working at an art studio in Kansas City. After briefly working as illustrators for a local newspaper company, they ventured into animation together. Iwerks joined Disney as chief animator on the Laugh-O-Gram shorts series beginning in 1922, but a studio bankruptcy would cause Disney to relocate to Los Angeles in 1923. In the new studio, Iwerks continued to work with Disney on the Alice Comedies as well as the creation of Oswald the Lucky Rabbit. Following the first Oswald short, both Universal Pictures and the Winkler Pictures production company insisted that the Oswald character be redesigned. At the insistence of Disney, Iwerks designed a number of new characters for the studio, including designs that would be used for Clarabelle Cow and Horace Horsecollar.

Pete (also named Peg Leg Pete, Bad Pete, and Black Pete, among other names) is a cartoon character created by Walt Disney and Ub Iwerks of The Walt Disney Company. Pete is traditionally depicted as the villainous arch-nemesis of Mickey Mouse, and was made notorious for his repeated attempts to kidnap Minnie Mouse. Pete is the oldest continuing Disney character, having debuted in the cartoon Alice Solves the Puzzle in 1925. He originally bore the appearance of an anthropomorphic bear, but with the advent of Mickey in 1928, he was defined as a cat.

Pete appeared in 67 animated short films between 1925 and 1954, having been featured in the Alice Comedies and Oswald the Lucky Rabbit cartoons, and later in the Mickey Mouse, Donald Duck, and Goofy cartoons. During World War II, he played the long-suffering sergeant trying to make a soldier out of Donald Duck in a series of animated shorts.

The Chain Gang is a 1930 Mickey Mouse animated film produced by Walt Disney Productions for Columbia Pictures, as part of the Mickey Mouse film series. It was the twenty-first Mickey Mouse short to be produced, the sixth of that year. It is one of a group of shorts of strikingly uneven quality produced by Disney immediately after Ub Iwerks left the studio.

The cartoon was primarily drawn by Norm Ferguson, and featured a pair of bloodhounds, who helped to track down Mickey after his prison escape. Although these dogs were not named, the style in which they were drawn makes them clear forerunners of Pluto, who first officially appeared a few months later in The Picnic. The animation for one of the bloodhound scenes in The Chain Gang was recycled as Pluto in four later cartoons. Additionally, a few scenes contain reused animation from the Oswald The Lucky Rabbit cartoon Sagebrush Sadie.

Julius the Cat is a fictional anthropomorphic cat created in 1922 by Walt Disney. He first appeared in Disney's Laugh-O-Gram comedies, making him the predecessor of Oswald the Lucky Rabbit and Mickey Mouse. Julius is an anthropomorphic cat, appearing intentionally similar to Felix the Cat. Later appearing in Disney's Alice Comedies, he gradually became the focus of the series to the point Disney abandoned live action for pure animation on subsequent projects. The first short entered Public Domain on January 1st, 1997 under the copyright act of 1976, and the final short entered Public Domain on January 1st, 2023 under the copyright act of 1998.

Julius was the first of Disney's animated protagonists to battle Pete, their oldest continuing character.