Megadeth is an American heavy metal band from Los Angeles, California. Guitarist Dave Mustaine and bassist David Ellefson formed the band in 1983 shortly after Mustaine's dismissal from Metallica.
A pioneer of the American thrash metal scene, the band is credited as one of the genre's "big four" with Anthrax, Metallica and Slayer, responsible for thrash metal's development and popularization.