The line comes from Monty Python and the Holy Grail, the 1975 comedy in which a narrator announces much rejoicing after the Killer Rabbit is defeated with the Holy Hand Grenade. Its deadpan delivery made it easy to lift out of context, and editors soon began using it online as a shorthand for victory, relief and absurd celebration. Decades later it survives because it fits almost any happy ending, from gaming wins to everyday good news, without needing the film itself to explain the joke.