Horror’s mainstream appeal varies pretty wildly from decade to decade, but there seems to be at least one big breakout hit every decade. The 1970s had a few, but I’d argue that the one that stands above the others for sheer cultural impact was The Exorcist. Ushering in a whole standard in special effects, it was a huge hit -- and it still really disturbs people to this day, too. Ask your parents which movie freaked them out when they were young, and you can virtually guarantee that the answer is The Exorcist, irrespective of how old they were when it was released.
Regan goes through multiple stages of possession (and makeup) during the film. She starts out looking like a normal 12-year-old girl, then begins to look worse and worse as the demon Pazuzu exerts greater control over her. This Mini depicts Regan in full-blown possessed mode – her face is green and has slashes across it, while vomit stains her nightgown. Given that they could have reused much of the sculpt, it’s almost surprising that they didn’t also do a “plain” Regan, though I guess we may see that in a future series of Horror Classics.
I’ve only watched the film once or twice myself; I did enjoy it, but found it a little long. If I’d seen it on first release, I think I would have found it terrifying – but if ever there was a movie that suffered for being influential, it’s The Exorcist. Even at age 19, I’d already seen it parodied dozens of times in other media, read books on special effects that explained how virtually every shot in the movie was executed and heard all the stories about its “cursed” production. For the most part, the ability to outright shock had been lost, though it certainly still evokes an eerie atmosphere. Your own mileage may vary, of course. But good does ultimately triumph over evil, which places it into a bit of a contrast with many of the films it influenced, where the villain arguably is the hero (Halloween, Friday the 13th, A Nightmare on Elm Street et al).