The best horror movie of 2018 is not what you think

Despite what you might have heard from Vogue magazine when they decided to pontificate about horror movies for a minute, 2018 was actually a pretty good year for the horror genre. There were so many good films of the horror and horror-adjacent oeuvres that it would be basically impossible to keep up with them all, even if you were really trying.
The styles were wide and ranging, from the Nazi zombie madness of Overlord to the filmed-on-an-iPhone psychological suspense of Unsane to the subtle, "this ghost story is actually about the evolution of class structures in post-war Britain" Masterpiece Theatre sensibilities of The Little Stranger. There were indie gems like Summer of '84 and Ghost Stories, but even wide-release franchise sequels like The First Purge and Unfriended: Dark Web came out blazing and improved on their series. You had thought-provoking sci-fi horror like Upgrade and Annihilation as well as folk horror in the form of Gareth Evans' Apostle, plus stunning foreign horror films making their English-language debuts in 2018.
That's a lot of good stuff to choose from, which is maybe not surprising given how movies like The Nun are burning up the box office and well-crafted spookums are starting up those tired "this horror movie is so good, maybe it's not actually horror" discussions among critics. But between box office boffo and the certified fresh, what's the best horror flick of the year?