Dave Grohl's ascent to icon status has just about everything to do with his roles as both Nirvana's drummer and leader of the hooky radio staple Foo Fighters. But it would be negligent to discount the importance of Grohl's star-quality work as a drummer-for-hire: His insistent bash played as big a role as any in Queens Of The Stone Age's transformation from stoner-rock cult act to mainstream hard-rock titan. He uses that goodwill to even nobler ends with his supergroup-of-sorts Probot, which finds Grohl lending characteristically sturdy, pummeling support—he writes all of the band's music, and plays most of the instruments—to tracks featuring a wide variety of wizened heavy-metal frontmen. As warm in its intentions as a record can be while still featuring King Diamond, Probot uses Grohl's presence as a Trojan horse to expose young fans to singers from the likes of Venom, Voïvod (a source of both musical influence and the album's instantly recognizable cover art), D.R.I., Trouble, Corrosion Of Conformity, and more. Grohl isn't the only ringer in Probot's impressive arsenal: Soundgarden's Kim Thayil pops up here and there, while Sepultura and Soulfly frontman Max Cavalera lends his full-throated star power to "Red War." Naturally, many of Grohl's handpicked vocalists aren't in their leather-lunged prime at this point, and Probot is far too bruising and uncompromising to pack much crossover appeal. But it's a righteous and wholly legitimate throwback to old-school metal's power and fury, with countless bonus points for the spotlight it throws on indestructible, eternally winning Motörhead frontman Lemmy.