Grindcore is an extreme fusion genre of heavy metal and hardcore punk that originated in the mid-1980s, drawing inspiration from abrasive-sounding musical styles, such as thrashcore, crust punk, hardcore punk, extreme metal, and industrial. Grindcore is considered a more noise-filled style of hardcore punk while using hardcore's trademark characteristics such as heavily distorted, down-tuned guitars, grinding overdriven bass, high-speed tempo, blast beats, and vocals which consist of growls, shouts and high-pitched shrieks. Early groups like Napalm Death are credited with laying the groundwork for the style. It is most prevalent today in North America and Europe, with popular contributors such as Brutal Truth and Nasum. Lyrical themes range from a primary focus on social and political concerns, to gory subject matter and black humor. A trait of grindcore is the "microsong" much shorter than average for punk or metal; several bands have produced songs that are only seconds in length. British band Napalm Death holds the Guinness World Record for shortest song ever recorded with the one-second "You Suffer" (1987). Many bands, such as Agoraphobic Nosebleed, record simple phrases that may be rhythmically sprawled out across an instrumental lasting only a couple of bars in length. A variety of subgenres and microgenres have subsequently emerged, often labeling bands according to traits that deviate from regular grindcore; including goregrind, focused on themes of gore (e.g. mutilation and pathology), and pornogrind, fixated on pornographic lyrical themes. Another offshoot is cybergrind which incorporates electronic music elements such as sampling and programmed drums. Although influential within hardcore punk and extreme metal, grindcore remains an underground form of music. Source: Wikipedia (en)