Ralphie the Buffalo is the name of the live mascot of the University of Colorado Buffaloes. The current Ralphie, nicknamed Brandy, is the seventh bison to fill the role since 1967.

Ralphie is best known for running a horseshoe pattern around Folsom Field prior to each half of home football games. She begins each run as the public address announcer exclaims "Here comes Ralphie!" and typically leads the football team as they enter the playing field. She has frequently been named one of the best mascots in sports.

While commonly referred to as a buffalo, Ralphie is actually an American bison. Due to their smaller size, reduced strength, and less-aggressive temperament, female bison have always been chosen as Ralphie as opposed to males. She can reach speeds of 25 miles per hour, and it traditionally takes five handlers to guide her around the field. The team of approximately 15 "Ralphie Handlers" are student-athletes that earn varsity letters for their efforts. They spend more than 20 hours per week training, practicing, and caring for Ralphie, while rotating the privilege of running with her at the games.

The buffalo was officially chosen as the University of Colorado's mascot in 1934. Live bison appeared on the sidelines at football games on-and-off for the next several decades. In 1957, Mr. Chips became the first named bison affiliated with the program.

The bison that became Ralphie I was donated by John Lowery, the father of a CU student in 1966. While she only watched from the sidelines originally, by 1967, it was determined that she would run on the field prior to games to intimidate the other team. The basis of her name and its original spelling – "Rraalph" – are of disputed origin. Her name changed to Ralphie by the end of her first full season. Ralphie I was kidnapped in 1970 by Air Force Academy students. She was also named the school’s 1971 Homecoming Queen.

All subsequent Ralphies have also been donated to the university. Ralphie II debuted before the second half of the final home game in 1978, after Ralphie I ran for the final time before the game. In 1986, Oklahoma State pranksters snuck into their college’s veterinary clinic and sprayed painted “OSU” on Ralphie's back in orange letters. On September 19, 1987, Ralphie II unexpectedly died the night after she ran during a game. Ralphie III was already preparing to take over in 1988, but was pressed into action sooner than anticipated. She became the first Ralphie to wear the blanket around her body. Ralphie IV was abandoned by her herd and attacked by a coyote before being rescued and donated to the university. Ralphie V was known as the most powerful and fastest of all the Ralphies. Ralphie VI was introduced to the public in 2021 at just 15 months of age and 500 pounds. She was retired in August 2025 due to an “indifference to running.” On September 19, 2025, it was announced that Ralphie VII would make her debut at the game against Wyoming the next day.

The Ralphie Handlers are a group of approximately 15 varsity student-athletes that volunteer 20 or more hours per week for the program in physical training, practicing, making appearances, and caring for Ralphie.

Initially called "The Men Who Run with Ralphie," the name was changed to "Ralphie Runners" in 1970. As the responsibilities and duties of the students on the team increased from just running with Ralphie to assisting in her overall care and maintenance, the name "Ralphie Handlers" was adopted in the 1980s. Handlers first started earning varsity letters in 1987. Even though the Handlers do not fall under NCAA jurisdiction, the Athletic Department still holds them to the same standards as other varsity athletes in the department. The first woman joined the Ralphie Handlers in 1992.