Adam Nathaniel Yauch ( YOWK; August 5, 1964 – May 4, 2012), also known by the stage name MCA, was an American rapper, bassist, filmmaker, and a founding member of the hip hop group Beastie Boys. Besides his musical work, he also directed many of the band's music videos and did much of their promotional photography, often using the pseudonym Nathanial Hörnblowér for such work.
Yauch founded Oscilloscope Laboratories, an independent film production and distribution company based in New York City.
