múm are an experimental Icelandic musical group whose music is characterized by soft vocals, electronic glitch beats and effects, and a variety of traditional and unconventional instruments.
The band was formed in 1997 by original members Gunnar Örn Tynes and Örvar Þóreyjarson Smárason, who were joined a year later by twin sisters Gyða and Kristín Anna Valtýsdóttir. According to Kristín, the band's name was not intended to mean anything. In 2002, after the first American tour, Gyða left the band to return to her studies in Reykjavík. Shortly after Gyða left, Ásthildur Valtýsdóttir joined for singing duties and Serena Tideman replaced Gyða on cello for a European tour. Then the ensemble evolved to include Ólöf Arnalds and Hildur Guðnadóttir. In early 2006, Kristín also left the band, although it was not officially announced until November 23 of that year.
Despite the departure of some of its members múm has remained together as a collective of musicians. Their fourth album, recorded during 2006, was released on 24 September 2007, entitled Go Go Smear the Poison Ivy.
During a 22 May 2009 concert in Burgos, Spain, múm played songs from their new album Sing Along to Songs You Don't Know. It was released as a download through Gogoyoko on 17 August 2009, and on CD on 24 August 2009.