The FBI saw mobsters emulating the movie – kissing rings, carrying themselves like the characters, and using the term Godfather (which was invented by Puzo – possibly inspired by the Kefauver report, which noted crime boss Frank Costello was godfather to another criminal’s child). The film’s score was played at weddings and parties – the Mafia’s “national anthem,” said Selwyn Raab. 

Salvatore “Sammy the Bull” Gravano – who said he “floated” out of the cinema because of how brilliantly The Godfather depicted their lifestyle – admitted to pilfering Don Corleone’s catchphrases. “I would use lines in real life like ‘I’m gonna make you an offer you can’t refuse,’” he told The New York Times. “And I would always tell people, just like from The Godfather, ‘If you have an enemy, that enemy becomes my enemy.’”

In 2001, a former Pennsylvania police officer told the Irish Independent how every raid on a mobster’s house found the Godfather films on video. Joe Coffey, a former rackets investigator, told the documentary the same thing. “When we come in, with the guns out and the whole routine, they’ve got the tape of The Godfather in the television VCR,” he said.

Its influence may be even more sinister. In May 1991, building contractors from Palermo, Sicily found a horse’s head in a car. Ten years later, also in Palermo, another horse’s head was found in a car – this time with a knife between its eyes. In 2008, a bread shop owner in Villafranca Padovana, northern Italy was sent a donkey’s head after refusing to pay protection money to a low-level gang (“The man didn’t know the donkey, he didn’t own the donkey, he doesn’t care about donkeys. It didn’t make sense. It was the work of idiots,” a police spokesman said). 

Sammy the Bull credited the film for his own crimes. “I killed 19 people,” he told The New York Times. “I only did, like, one murder before I saw the movie.”