Sweet Leaf is the opening track on Black Sabbath's 1971 album Master of Reality, and its first seconds feature a cough before the band's famous riff begins. The opening is widely recognised among heavy metal fans, instantly signalling the song's subject and its laid-back, rebellious attitude. Online, the isolated cough is shared on its own as a reaction sound, detached from the full track, and is commonly used in edits about smoking, rock culture and ironic overconfidence.