Back in 2006, I wondered what happened to Clarabelle Cow but by the end of that year, Mickey Mouse Clubhouse was made and she has been a regular character. She has often been called an auxiliary character and never had a star position. But her boyfriend Horace Horsecollar has been left out in America.
Clarabelle Cow in Mickey Mouse Clubhouse, even though she hasn't had her own episode, she has had pivotal plot points like having a birthday cake that Pete stole (and Pete making a hilarious imitation of her), having a pet parade and hiring Mickey and his friends as a band. Clarabelle has been paired in the past with Goofy and here is no exception. Horace Horsecollar has not appeared on Mickey Mouse Clubhouse yet. Probably the reason Horace has not appeared on Mickey Mouse Clubhouse is because maybe there are too many male characters and they need Clarabelle to fill in the female role. Ludwig Von Drake, Chip 'n' Dale, Willie the Giant, Figaro the Kitten, Humphrey the Bear, Salty the Seal, and Mortimer Mouse have made guest appearances.
Horace Horsecollar was created by Ub Iwerks and Walt Disney. He is an anthropomorphic horse, one of Mickey Mouse's best friends and the boyfriend of Clarabelle Cow. Horace first appeared as Mickey's plough horse in the cartoon "The Plowboy" in 1929. He next appeared later that same year, in "The Jazz Fool", and after that he became a regular member of the Disney supporting cast, along with Clarabelle Cow, Clara Cluck and others even more minor.
Horace appears in the video game Kingdom Hearts II, residing in Timeless River. In Kingdom Hearts Birth by Sleep, his only other appearance, he is shown to reside in Disney Town. In Kingdom Hearts II, he does not play any essential role other than walking around the Cornerstone Hill with Clarabelle Cow and Clara Cluck.
In the videogame Epic Mickey, The classic black and white Horace Horsecollar lives in Wasteland, having become a private detective and good friends with Oswald the Lucky Rabbit during his time down there. In addition, he and Clarabelle Cow have kept alive the romance they had before being sent to Wasteland. He admits he "Gets Clumsy Around Her" to Mickey.
Horace reappears in House of Mouse as the club's technician, often starting up the cartoons and TV reports shown on the club's big screen; he often did this by attacking the DVD player with a mallet or punching glove. As a running gag, Mickey often asks him what is wrong, causing him to list things that are wrong in the world (i.e. "The Internet's too dang slow!"), prompting Mickey to rephrase "No, what's wrong in here?" One of his notable appearances is in the series pilot episode "The Stolen Cartoons". Pete steals the clubs cartoons by breaking into Horace's tech room and taking all cartoons.
There has been a petition for Horace to be on the Clubhouse. He has been considered a 'forgotten' character but he still appears in Italian comic books, as well as Clarabelle would is a big character in Italy where it seems he is a handyman.