Probot was a heavy metal side project of ex-Nirvana drummer and Foo Fighters guitarist and lead-singer Dave Grohl. An album was recorded out of the material and released in February 2004. It featured one single entitled "Centuries of Sin / The Emerald Law".
The album features guest vocals from Eric Wagner (Trouble), Snake (Voivod), Cronos (Venom), Lemmy (Motorhead), Wino (Saint Vitus), Max Cavalera (Sepultura), Mike Dean (Corrosion of Conformity), Kurt Brecht (DRI), Lee Dorrian (Cathedral), Tom G. Warrior (Celtic Frost), King Diamond (Mercyful Fate) and Jack Black (Tenacious D).