Biography: Probot Dave Grohl has voiced his appreciation of heavy metal numerous times over the years, whether it be trying to convince his Nirvana bandmates to have Sepultura open shows on the In Utero tour or playing with the Foo Fighters alongside Slayer, Pantera, and Black Sabbath at Ozzfest 1998 in the U.K.. But he was never so exuberant about his metal fixation until he issued the all-star project Probot in the early 21st century. As a teen growing up in Washington, D.C., during the early '80s, Grohl and a friend became interested in such (then) cult metal bands as Iron Maiden and Motörhead, before discovering a mail order ad for a record service named "End of the Rainbow," which specialized in tracking down the newest releases from the metal underground. Looking for bands that were "fast and heavy," the duo found their gold mine when they heard such classics as Metallica's Kill 'Em All and Mercyful Fate's Melissa. From there, Grohl continued to hunt down further releases from the metal underground, which led to an appreciation for such groups as Trouble and Celtic Frost, even though he was playing in hardcore bands at the time. As just about any rock fan knows, Grohl spent the '90s playing with two of the decade's most successful alternative rock acts, Nirvana and the Foo Fighters. And while both acts included elements of hard rock/metal in their sound, Grohl started to feel that he was becoming too closely linked to the more melodic side of rock. So when he came into some free time shortly after the dawn of the 21st century, he constructed a plan. Grohl began writing, playing (almost entirely himself), and recording an album's worth of metal tunes that harked back to the sound of the aforementioned bands of the '80s. When it came to laying down vocals, Grohl came up with another idea -- instead of handling the vocal duties himself, he would get the singers from his favorite metal bands of yesteryear to lend a hand (as well as contribute lyrics). A fine plan, but hunting down some of these MIA chaps proved quite difficult -- at least before Grohl's pal, former Chavez/Zwan guitarist Matt Sweeney, offered to lend a hand in the "location" department. Soon after, Grohl was receiving confirmations from the likes of Cronos from Venom, Snake from Voivod, Eric Wagner from Trouble, and Wino from Obsessed, as well as such more renowned names as Lemmy and King Diamond (with former Soundgarden guitarist Kim Thayil supplying some additional riffs to the project). Despite the project getting press coverage from the get-go, it took a few years to finally see the light of day, as record label red tape halted its release (as well as the simple fact that no major labels would commit to backing an album showcasing cult metal singers of the '80s). But Grohl eventually found a taker with the indie doom metal label Southern Lord, which issued the self-titled album (as a CD and double vinyl record) in February of 2003.