Special Guest: Lots and lots:
Dino Cazares and Burton C. Bell of Fear Factory on "Eye for an Eye"
Fred Durst and DJ Lethal of Limp Bizkit on "Bleed"
Chino Moreno from Deftones on "First Commandment" and "Pain"
Benji Webbe of Skindred on "Quilombo" and "Prejudice"
Grady Avenell of Will Haven on "Pain"
Corey Taylor of Slipknot and Stone Sour on "Jumpdafuckup"
Sean Lennon, son of John Lennon from The Beatles, on "Son Song"
Tom Araya from Slayer on "Terrorist"
Cristian Machado of Ill Nino on "One"
David Ellefson of Megadeth on "Riotstarter"
Reggae singer Nemanja Kojic on "Innerspirit"
David Vincent from Morbid Angel on "Blood Fire War Hate"
Dave Peters of Throwdown on "Unleash"
Greg Puciato of The Dillinger Escape Plan on "Rise of the Fallen"
Tommy Victor of Prong on "Lethal Injection"
Travis Ryan from Cattle Decapitation on "World Scum"
Dez Fafara from Coal Chamber and DevilDriver on "Redemption of Man by God"
Jamie Hanks of I Declare War on "Fallen"
Neil Fallon of Clutch on "Ayatollah of Rock 'n' Rolla"
And finally (so far), Mitch Harris of Napalm Death on "K.C.S."