"Piranha Brothers" is a Monty Python sketch that was first seen in the first episode (titled "Face the Press") of the second series of Monty Python's Flying Circus. Originally transmitted on the television comedy on September 15, 1970, the premise is a BBC current affairs documentary program, inexplicably entitled Ethel the Frog, retrospectively covering the exploits of the fictional brothers Doug and Dinsdale Piranha. The sociopathic criminals employed a combination of "violence and sarcasm" to intimidate the London underworld and bring the city to its knees. Dinsdale is also described as being afraid of "Spiny Norman", an apparently imaginary gigantic hedgehog whose reported size varied on Dinsdale's mood. During the end of the sketch, which also ends the episode, the creature is apparently revealed as real and appearing beside various English landmarks as the credits roll.
The sketch constitutes a loose pastiche of the real-life story of the Kray twins, famous gangsters who maintained an underground criminal outfit based in the East End of London in the 1950s and 1960s. Doug and Dinsdale Piranha were loosely based on Reggie and Ronnie Kray, and the policeman who pursued them, Harry "Snapper" Organs, was loosely based on the policeman who led the investigation against the Krays, Detective Superintendent Leonard "Nipper" Read. However, the Piranhas' described methods seem to resemble more closely those used by the rival the Richardson Gang and their associate "Mad" Frankie Fraser. The bizarre creature "Spiny Norman" is possibly a subtle reference to the notorious former head of the London Drug Squad, Detective Sergeant Norman Pilcher.