Hollywood Undead is an American rock band formed in 2005 in Los Angeles, California. The group is known for its unique blend of rock, rap, and electronic music, often featuring multiple vocalists. They gained popularity with their debut album, Swan Songs, released in 2008, which included hit singles like "Undead" and "Hear Me Now." The band members are recognized for wearing distinctive masks during performances, adding an element of mystery to their image. Over the years, Hollywood Undead has released several albums, including American Tragedy and Five, and has built a dedicated fan base through energetic live shows and engaging music.