There are mutliple artists with this name:
1) Infest was an influential American hardcore punk band, formed in Valencia, CA, suburb of Los Angeles, from 1986 to 1996. They were instrumental in pioneering powerviolence, a musical cross-breeding of hardcore and youth-crew. Members were Joe Denunzio (vocals), Matt Domino (guitar), Dave Ring (bass) and Chris Clift (drums).
The band , while not coining the term powerviolence, were definitely pioneers of it.