9. Cannibal Holocaust
Though it's proven decidedly trickier to dupe moviegoers since the worldwide adoption of the Internet over the last 20 years, back in 1980 Ruggero Deodato had everyone fooled with his nauseatingly authentic found footage horror Cannibal Holocaust.
The film follows a group of American anthropologists who head into the Amazon rainforest in an attempt to locate a missing film crew who headed there to document an indigenous cannibal tribe.
As you can imagine, it doesn't go well for any of the American interlopers, and upon original release, many believed that Cannibal Holocaust was in fact a snuff film.
This was largely a result of not only the film's believably gritty visual style and stunningly realistic gore effects, but also the fact that Deodato had his cast sign contracts agreeing not to appear in any other media for a year after the movie's release.
This led to Deodato being dragged before the Italian courts on charges of obscenity and murder, requiring him to get the actors to come together for a TV interview and confirm their living status.
Furthermore, he also had to show the courts how the film's infamous impalement scene - by far its most convincing effect - was achieved.
Though the director was eventually cleared and sanctions against the film were lifted, Cannibal Holocaust remains hugely controversial today due to its very real depictions of animal slaughter, and four decades on, it's lost not a shred of its queasy believability.