L.D. 50 is the debut studio album by the American heavy metal band Mudvayne, released on August 21, 2000. The album is widely considered a defining release in the nu-metal and alternative metal scenes of the late 1990s and early 2000s, blending elements of progressive metal, math metal, and industrial rock with a heavy dose of experimentalism mixing aggressive riffs, groovy basslines, intense drumming, and gritty, fluctuating vocals (from clean singing to deep growls). The band's complex arrangements, aggressive sound, and unique approach to metal made L.D. 50 a critical success and a fan favorite. The album title L.D. 50 is a reference to 'lethal dose, ' referring to the lethal dose of a substance needed to kill 50% of a population; the band used it as a metaphor for the album's intense and overwhelming nature. The album features the singles "Dig" and "Death Blooms".