Hollywood Undead is an American rap rock band from Los Angeles, California, formed in 2005. All of the band members use pseudonyms and previously wore their own unique mask, most of which were based on the common hockey goaltender design. The band currently consists of five members: J-Dog, Funny Man, Johnny 3 Tears, Charlie Scene, and Danny. They released their debut album, Swan Songs, on September 2, 2008, and their live CD/DVD Desperate Measures, on November 10, 2009. Their second studio album, American Tragedy, was released April 5, 2011. Their third studio album, titled Notes from the Underground, was released on January 8, 2013.

Rap rock is a music genre that developed from the early to mid-1980s, when hip hop DJs incorporated rock records into their routines and rappers began incorporating original and sampled rock instrumentation into hip hop music. Rap rock is considered to be rock music in which lyrics are rapped, rather than sung. The genre achieved its greatest success in the late 1990s and early 2000s.