Crystal Castles are an experimental electronic band from Toronto, Ontario, Canada, consisting of producer Ethan Kath and lyricist and vocalist Alice Glass. Crystal Castles are known for their chaotic live shows and their lo-fi home productions. The duo released many limited EPs between 2006 and 2007, and two eponymous albums in 2008 and 2010 to widespread critical acclaim. Their debut album was included in NME's "Top 100 Greatest Albums of the Decade" list at #39.

Ethan Kath met Alice Glass in Toronto when she was 15. After hearing her sing in a local punk band, Fetus Fatale, Kath asked her to record vocals over tracks he had been working on since 2003. After writing some lyrics, she went to a studio to record them, where her soundcheck was secretly recorded. Six months later, Kath uploaded the finished songs to the internet, including "Alice Practice," the results of the mic check, under the band name Crystal Castles, a tribute to a song featured in the cartoon She-Ra which featured the lyric "The fate of the world is safe in Crystal Castles." In 2005 songs such as "Magic Spells", "Untrust Us", and "Alice Practice" grew popular online, and he began receiving offers from record labels. This news was especially shocking to Glass, having lost touch with Kath since the recording and up to that point unaware "Alice Practice" even existed. The song became the band's first official release in 2006 on a limited vinyl which was released by London's Merok Records.