Two weeks ago, the Knotfest marked the return of Slipknot. The three-day festival featured a killer lineup, and more importantly, two full nights of headlining sets from Slipknot, their first shows in support of .5: The Gray Chapter, which would go on to be the #1 album in the country. Photographer and Metal Insider contributor Racheal Mattice was there, and captured some shots of some of the bands playing, including Anthrax, Testament and Black Label Society.