Dave Mustaine was the original guitarist in Metallica, but they fired him in 1983 due to his chronic alcoholism and personality clashes with the rest of the band. Pissed when they gave him the boot, he immediately decided to form a group that would wipe Metallica off the map. He didn't succeed with that, but Megadeth did evolve into one of the most potent metal forces of the Eighties. The lineup has changed a lot over the years, but Mustaine has always stayed at the helm, and in 2010 the group hit the road with Metallica, Slayer and Anthrax. The show ended with all four groups jamming, and Mustaine and the rest of Metallica finally shared the stage again.