The incident took place at WWE NXT's Aftershock festival on Friday (October 23)
Singer helped voice The Fisher King in recent episode
Track taken from the group's latest album '.5: The Gray Chapter'
Band will play live dates in Cardiff, London, Birmingham and Leeds next February
Metal singer will lend his voice to the Fisher King character, described as an 'alien warlord'
Singer says he will also go to every single gig if the band get back together
The clip has been viewed nearly 400,000 times
Band describe the event as 'absolutely sickening'
Slipknot man is sick of bands being "elitist to the point of pricky"
Frontman reveals plans for double album with film to accompany it