A mashup or bootleg is a song or composition create from the combination of the music from one song with the a cappella from another (also mash up and mash-up). These songs may be considered part of the European bastard pop musical genre. "A mash-up is a song created out of pieces of two or more songs, usually by overlaying the vocal track of one song seamlessly over the music track of another...Mash-ups are incredible fun and a fascinating way to reexperience some of your favorite tunes."