The phrase grew out of TikTok slang, where 'erm' is used as a mock-hesitant filler and 'sigma' refers to the internet's ironic lone-wolf archetype. Combined, the line became a shorthand reaction in short-form videos, gaming clips, and reaction edits, usually aimed at moments that feel both confusing and oddly impressive. Its appeal lies in how instantly recognisable it is to viewers steeped in that online humour, and because the delivery is so short, it slots easily into edits without overpowering the visual joke.