Powerviolence (sometimes written as power violence), is a raw, dissonant sub-genre of hardcore punk. The style is closely related to thrashcore and grindcore. Musically, powerviolence bands focus on speed, brevity, bizarre timing breakdowns, and constant tempo changes. Powerviolence songs are often very short; it is not uncommon for some to last less than 30 seconds. Some groups, particularly Man Is the Bastard, took influence from sludge metal and noise music. Lyrically and conceptually, powerviolence groups were very raw and under-produced, both sonically and in their packaging.