What duo  was an American rapper and record producer apart of , who had a guest appearance in  the second album by American hip hop duo 1982 ?
Havoc (musician) Kejuan Muchita (born May 21, 1974), better known by his stage name Havoc, is an American rapper and record producer. He was one half of the hip-hop duo Mobb Deep.
Run-DMC Run-D.M.C. was an American hip hop group from Hollis, Queens, New York, founded in 1981 by Joseph Simmons, Darryl McDaniels, and Jason Mizell. Run-D.M.C. is widely acknowledged as one of the most influential acts in the history of hip hop culture. Run-D.M.C. is one of the most famous hip-hop acts of the 1980s who, along with LL Cool J, The Beastie Boys, and Public Enemy, signified the advent of the new school of hip-hop music. Run-D.M.C. were the first group in the genre to have a gold album ("Run–D.M.C.", 1984) and be nominated for a Grammy Award. They were the first to earn a platinum record ("King of Rock", 1985), the first to earn a multiplatinum certification ("Raising Hell", 1986), the first to have videos on MTV, and the first to appear on "American Bandstand" and the cover of "Rolling Stone". Run-D.M.C. was the only hip hop act to perform at Live Aid in 1985.