A parody, also called a spoof, a send-up, a take-off, a lampoon, a play on, a caricature or a joke, is a work which is created to imitate and/or make fun of or comment on an original work—its subject, author, style or some other target—by means of satiric or ironic.
Parody music usually falls under Fair Use laws. A great example of a parody music artist is Weird Al Yankovic.