Released on the 1983 album Kill 'Em All, this track stands as a defining moment in Metallica's transition from thrash metal to heavy metal. The song features a distinctive, repetitive guitar riff that became a staple of the band's live performances and a signature element of their early discography. Lyrically, it explores the physical and emotional pain of dental procedures, using the metaphor of anesthesia to describe the numbness required to endure suffering. The recording captures the raw energy of the band's formative years, showcasing James Hetfield's driving rhythm and Lars Ulrich's pounding drums. It remains a cornerstone of their catalog, often cited as a key track that helped establish their status as one of the most influential heavy metal acts of the 1980s.