Mr. Bungle is an American experimental rock band formed in Eureka, California, in 1985. Having gone through many incarnations throughout its career, the band is best known for its experimental rock period. During this time, it developed a highly eclectic style, cycling through several musical genres, often within the course of a single song, including heavy metal, avant-garde jazz, ska, disco, and funk, further enhanced by frontman Mike Patton's versatile singing style. This period also saw the band utilizing unconventional song structures and samples; playing a wide array of instruments; dressing up in masks, jumpsuits, and other costumes; and performing a diverse selection of cover songs during live performances.

The band was founded as a death metal project while the members were in high school. It is named after a character in the 1960 children's educational film Beginning Responsibility: Lunchroom Manners, as featured in the 1981 HBO special The Pee-wee Herman Show. Mr. Bungle released four demo tapes in the mid-to-late 1980s. On the back of Patton's success as frontman of Faith No More, the band was signed to Warner Bros. Records in 1990 and released three studio albums between 1991 and 1999 in the eclectic, experimental style it became known for. In the band’s early days and up to the second album, The band toured in 1999 and 2000 to support its third album before going on an indefinite hiatus that was confirmed as a dissolution in 2004. It reunited as a thrash metal band for a series of shows in February 2020 to perform its 1986 demo album The Raging Wrath of the Easter Bunny with Anthrax guitarist Scott Ian and former Slayer drummer Dave Lombardo. The band then returned to the studio to re-record the demo as a professional album, released in October of that year.

Mr. Bungle has gone through numerous lineup changes, with Patton, guitarist Trey Spruance, and bassist Trevor Dunn the sole consistent members. The band was based in San Francisco during its tenure with Warner Bros. During much of the band's existence, it was in a public dispute with Red Hot Chili Peppers, particularly between Patton and Chili Peppers vocalist Anthony Kiedis.