I have a fascination with obscure movements and heretical sects such as the Bundschuh, the Lollards, the Waldensians, as well as the Hussites with their various splinter groups such as the Utraquists, Taborites and Orebites (who were often in conflict with each other if not the Church), but probably the most radical were the Adamites. Led by a blacksmith, who was known as both 'Adam & Moses', they paraded about naked in public ritualistic ceremonies, were anti-marriage, expressing free love and a propertyless society. They regarded themselves as avenging angels, with a mission to weild the sword throughout the world until all the unclean had been cut down. In 1421 this radical sect were exterminated not by the Church, but by fellow radicals the Taborites for being 'too radical'.
For anyone interested in these and other radical movements in history, Norman Cohn's 'Pursuit of the Millennium' covers these groups and sects with much depth.