During the All Hope Is Gone era and in the psychosocial music video Slipknot introduced their "Purgatory masks", these masks were large Mardi Gras versions of their death masks. The masks were made out of a material which is believed to be similar to papier-mâché and are full headed masks which are disproportionately larger than the band member's bodies. The masks were used in promotional photos taken at the farm/studio were they wrote and recorded All Hope Is Gone. The photos were used as teasers prior to the release of All Hope Is Gone as well as in the booklet of the album. The Purgatory masks were ceremonially burnt in the music video for "Psychosocial" (which was also shot at the farm/studio were they wrote and recorded All Hope Is Gone) because the masks represented their egos and they were destroying all which they meant.
Shawn More or less, we have these giant masks that we're wearing, called 'purgatory masks.' They're like giant death masks, and they represent ego.
“That was a Shawn Crahan idea,” laughs Jordison. “Those are Mardi Gras heads of our faces from the death masks we wore in the ‘Vermillion’ video. It’s just a teaser, but it’s totally genius. When I first heard about it, I was like, ‘Are you fuckin’ kidding me?’ But then I saw the results, and I was like, ‘I totally get it!’ He’s got a good vision, man; he’s a great artist.”