The word sussy comes from internet slang for suspicious, popularised by gaming and meme culture, where calling something sus became shorthand for playful distrust. Extended clapping has long been used online as a sarcastic applause meme, and combining the two creates a ready-made reaction for clips where someone is caught being shady. It circulates mainly in short-form videos and soundboards, where creators reuse it as a quick punchline without needing any dialogue. Its appeal is its simplicity: the slow applause alone tells viewers the moment deserves mockery, not praise.