The line comes from Monty Python's Flying Circus, first broadcast in 1970 in the Spanish Inquisition sketch. Michael Palin leads two fellow inquisitors in bursting into unrelated scenes whenever someone says they did not expect the Spanish Inquisition. The sketch became one of the group's most quoted bits, and the entrance line spread through reruns, quotes and later internet memes. Its structure makes it reusable for any surprise arrival, which is why it remains a staple reaction sound decades later.