The line comes from El Chapulín Colorado, the Mexican comedy series created by Roberto Gómez Bolaños that began in 1973. Bolaños played Chapulín, a well-meaning but cowardly hero whose red costume includes two vinyl antennae on his hood. In the story those antennae vibrate when danger or an enemy is near, giving him a warning nobody else has. The Portuguese dub made the catchphrase familiar in Brazil as Chapolin, and clips and soundboard copies now reuse the warning as a ready-made alert for danger jokes online.