Alternative metal (or alt-metal), is a style of heavy metal that emerged in the late 1980s, and had popularity in the 1990s alongside grunge, thrash metal, punk and groove metal. Alternative metal bands are often characterized by heavy metal guitar riffs, unconventional sounds within other heavy metal genres, and sometimes experimental influences to heavy music. Many bands have done singing, while some bands might do growls or screams or yelling like Static-X, Slipknot and Nothingface. But bands like Staind, Helmet and Soundgarden use mostly singing. Bands include System of a Down, Mudvayne, Static-X, Slipknot, Kittie, Nothingface, Drowning Pool, and Soundgarden.
Initially alternative metal appealed to alternative rock fans, since virtually all 1980s alt-metal bands had their influences in the American rock underground scene. Alternative metal bands emerged from hardcore punk (Biohazard, Corrosion of Conformity), noise rock (Helmet, The Jesus Lizard), grunge (Alice in Chains, Soundgarden), and industrial (Ministry, Nine Inch Nails). These bands never formed a distinct movement or scene; rather they were bound by their incorporation of traditional metal influences and openness to experimentation. Jane's Addiction borrowed from progressive rock and Living Colour injected funk into their sound, for example, while Primus includes influence from both progressive rock and funk, and Faith No More mixed progressive rock, funk and hip hop.