Crass were an English punk rock band that was formed in 1977, which promoted anarchism as a political ideology, a way of living, and a resistance movement. Crass popularised the seminal anarcho-punk movement of the punk subculture, and advocated direct action, animal rights, and environmentalism. The band both utilised and advocated a DIY punk ethic approach, producing sound collages, leaflets, albums, and films.
Crass practiced "direct action" by spray-painting stencilled graffiti messages around the London Underground system and on advertising billboards, coordinating squats, and organising political action. The band also expressed its ideals by dressing in black, military surplus-style clothing, and using a stage backdrop which amalgamated several "icons of authority" including the Christian Cross, the swastika, the Union Flag, and an Ouroboros.
The band were critical of punk subculture itself, as well as wider youth culture in general. Crass promoted the type of anarchism that eventually became more common in the punk music scene (see anarcho-punk). They are also considered involved with the art punk genre, due to their use of tape collages, graphics, spoken word releases, poetry and improvisation.