Slipknot is an alternative metal band from Iowa formed in 1995. The group has experienced several line-up changes, but its membership has not changed since 1999: Sid Wilson, Joey Jordison, Paul Gray, Chris Fehn, Jim Root, Craig Jones, Shawn Crahan, Mick Thomson and Corey Taylor. The band's sound has been described as "a threshing machine devouring a military drum corps." The band incorporates diverse vocal styles, typically involving growled vocals, melodic singing and even rapping while the lyrics generally follow a very aggressive tone. The band's musical influences include death metal as well as thrash metal, blues and hip hop.