Wikipedia
The Beelzebubs, frequently referred to as "The Bubs", is an all-male a cappella group of students from Tufts University that performs a mix of pop, rock, R&B, and other types of music while spreading their motto of "Fun through Song." Founded in 1962, they have toured in Europe, Asia, South America, and North America, and they competed in NBC's The Sing-Off in December 2009, finishing in second place.
The group is best known for providing song arrangements and background vocals for the fictional all-male a cappella glee club "The Dalton Academy Warblers" on the American TV series Glee, although the Bubs do not play club members on screen. Singles by the Warblers, with series stars Darren Criss and Chris Colfer performing lead vocals, have collectively sold over 1.3 million copies through March 2011. Due to their popularity, a full soundtrack album of the Warblers songs was released April 19, 2011 as Glee: The Music Presents the Warblers.
The Beelzebubs were the inspiration for the Barden University Treblemakers in the movie franchise Pitch Perfect, being one of the groups covered by Mickey Rapkin in Pitch Perfect: The Quest for Collegiate a Cappella Glory, the book the movies are loosely based on.