Powerviolence (sometimes written as power violence), is a raw and dissonant subgenre of hardcore punk. The style is closely related to thrashcore and grindcore. In contrast with grindcore, which is a "crossover" idiom containing musicological aspects of heavy metal, powerviolence is just an augmentation of the most challenging qualities of hardcore punk; like its predecessor, it is usually socio-politically charged and iconoclastic.

The term was coined by Matt Domino in 1989. The term was first mentioned in the song "Hispanic Small Man Power (H.S.M.P.)" by genre pioneer Man Is the Bastard. Its nascent form was pioneered in the late 1980s in the music of hardcore punk band Infest, who mixed hardcore punk elements with noisier, sludgier qualities of Lärm and Siege. The microgenre solidified into its most commonly recognized form in the early 1990s, with the sounds of bands such as Man Is the Bastard, Crossed Out, Neanderthal, No Comment, and Capitalist Casualties. Powerviolence groups took inspiration from Siege and Deep Wound, Cryptic Slaughter, Septic Death, Dirty Rotten Imbeciles, Negative FX and early Corrosion of Conformity. These precursors to powerviolence are grouped together as "thrash" or thrashcore.

Agoraphobic Nosebleed (abbreviated as ANb) is a grindcore band formed in 1994 in Springfield, Massachusetts, United States. Its line-up has changed often during the years, leaving the only permanent member Scott Hull (guitars, drum programming), also a guitarist in Pig Destroyer. The current line-up also includes vocalists Jay Randall, Kathrine Katz of Salome, and Richard Johnson of Enemy Soil and Drugs of Faith, who also plays bass guitar. Agoraphobic Nosebleed are one of the most well-known drum-machine grindcore bands, and have influenced many drum-machine grindcore bands.

The band is known for the brevity of its songs. Their album Altered States of America features 100 songs (including one hidden) in just under 22 minutes, with many songs of 5 seconds or less, and the longest song only 1:45.

Agoraphobic Nosebleed played their first live set at the 2003 New England Metal and Hardcore Festival. As their appearance was unscheduled, Pig Destroyer cut their set short so they could play two songs and an intro.