Performer(s) Appeared in Horace Horsecollar is a cartoon character created by Ub Iwerks and Walt Disney in 1929. He is an anthropomorphic horse who is one of Mickey Mouse's best friends. Characterized as a cheerful know-it-all, Horace helped Mickey on his sleuthing expeditions in the comics before Goofy assumed that role. He made frequent appearances in Mickey's cartoon shorts until 1942, but has since then continued to appear in comic book stories, video games, and television cartoons.