When filmmakers want to terrify you in "traditional" ways, they add a score that signals dread. If you a hear a shrieking violin or a Gothic choir or a devil baby's lullaby then brace yourself for a good old-fashioned nightmare.
Sometimes, though, the terror needs to spring from an unexpected place, and that's when it's time for an ironic soundtrack. Nothing reminds us that evil lurks in every corner like watching a murder set to "Both Sides Now."
Here are some tunes that underscore (ha!) why ironic terror is such a popular trope, as well as one hit that's just waiting to get splattered with blood.
I'm sure there are movies that used subversively horrifying soundtracks before Stanley Kubrick's A Clockwork Orange, but this is the standard bearer. "Singin' in the Rain" is a great song, full of wistful romance and memories of Gene Kelly on a lamppost, but in Kubrick's film, it's the anthem of a horrifying rape. The jolly tune makes the attack even more gut-wrenching, because it reminds us that for the attackers, the rape is just a lark.
(Warning: This scene is really disturbing, Don't watch with the kids around.)
The "bloody deeds and cheery tunes" approach has been carried on by recent flicks like American Psycho and David Fincher's The Girl With the Dragon Tattoo, and because those movies choose easy listening hits by Huey Lewis and Enya, they add extra commentary about the soullessness of the corporate music machine. Apparently, if you like "Orinoco Flow," then you're a sociopath. (But I'll support "Hip to Be Square" until I'm deep in the ground!)
It's a little cheap, if you ask me, but another good way to freak people out is to pair a scary moment with a children's song. Nothing creates dread like perverting the innocence of childhood, amirite? And if there's a ghost toddler floating around while a Jack-in-the-Box plays "Pop Goes the Weasel," then audiences will flip.
Tons of movies use this trick, including this fall's Insidious 2, which got some decent milage from "Row Row Row Your Boat:"
Don't you think it's time for Hollywood to gorify the wedding/engagement flash mob? We've been inundated with viral videos of bridesmaids doing choreography to Chris Brown's "Forever" and guys proposing while twenty friends dance to Christina Perri. Those things are almost always beautiful, which is why they're ripe for a horror makeover.
Obviously, the scene should be built around Bruno Mars' "Marry You," which inspired the best engagement flash mob I've ever seen. Seriously, this makes me cry EVERY TIME:
Now picture one of those street dancers getting devoured by an alien dog! We'd be storming into the theatre to see that movie, because it would rattle us to our viral core!