Some time later, inspired by the Santana album "Supernatural", Grohl decided to attempt collaborations with singers he had idolized. He came up with "my wish list of all of my favorite singers from this era which is '82 to '89 underground metal, and all the bands I listened to at the time: Eric Wagner from Trouble, Snake from Voivod, Cronos Venom, Lemmy and Wino," and started contacting the musicians, some of whom were reached by Grohl's friend Matt Sweeney given the Foo Fighters had restarted their tour. Grohl feared his fame built out of being "a stupid, middle-of-the-road, alternative-rock idiot" could drive the metal singers away, but many agreed immediately. Cronos would later explain that "I'm open for everything. And Dave's cool," detailing that Grohl's email opened with "a real fan letter" where he mentioned his longtime appreciation of Venom, and then explained about his idea of a metal album with all his metal heroes "to get something off his chest."