David Ellefson, American bass player and songwriter
David Warren Ellefson (born November 12, 1964) is an American musician, best known for his long tenure as the bassist for American thrash metal band Megadeth.

Ellefson initially became an accomplished bassist and honed his songwriting skills while leading several of his own bands through the club scene of North America's Midwest region before relocating to Los Angeles. He was then the bassist and co-founder of Megadeth from 1983 to their breakup in 2002, and again from 2010 to 2021. Ellefson co-founded The Lucid in 2021 alongside vocalist Vinnie Dombroski (Sponge), guitarist Drew Fortier (ex Bang Tango), and drummer Mike Heller (Fear Factory, Malignancy, Raven). In addition to playing bass guitar in Megadeth and The Lucid, Ellefson had various side projects, which include Temple of Brutality, F5, Killing Machine, and Metal Allegiance.