Experimental Rock (ɪkspɛ̀rəmɛ́ntəl rák) is a genre that is based on rock and is often used as a catchall for any rock music that does not fit into the traditional rock categories. Experimental Rock takes rock music to a completely different extreme by releasing the chains of traditional rock rules and expectations and experimenting with different forms of rhythm, instruments, and noise. Incorporating electronic elements and studio manipulation, The Velvet Underground is known as one of the first to introduce the sound to the world. Other groups, such as The Mother of Invention and Monks have found their sound in Experimental Rock.