The phrase comes from Vous êtes fous, the breakout single by Belgian hip hop group Benny B, released in 1989 and a huge hit in Belgium and France in 1990. Its repetitive shouted chorus made the line instantly memorable far beyond rap audiences, and it became a common spoken catchphrase. Decades later the clip resurfaced on soundboards and in short videos, where creators reuse the familiar shout as a ready made reaction. Its longevity comes from that chorus, simple enough to quote in any context.