John Carpenter's f/x heavy remake of The Thing (1982) contains a brief interaction between man and monster that graphically foregrounds the chief problematic of the horror film. Under attack from a shape-shifting parasite that readily jumps from species to species and host to host, the members of an Arctic research team attempt to hold their own. In a rare moment of human advantage, the beleaguered company manages to temporarily isolate the chameleon invader. Sequestered in the host head of a decapitated human, the parasite seeks escape by morphing into a hermit-crab-and-skull combination that scuttles to freedom on scaly legs. As the beast of fusion skitters away, a gape-jawed, goggle-eyed technician exclaims, “You gotta be fucking kidding!”

Composed in equal measure of ontological and epistemological bewilderment, this profane cry exactly delimits the boundaries of the genre. Bound between what can and cannot be, the astonished prole must decide between exclusive options. Is the crab head that once crowned a colleague's body a macabre joke, eyes playing tricks, or is the foul crustacean an oracle? Cast between the antipodes of raillery and revelation, the lab tech and his double, the protagonist and the audience must decide if seeing is truly believing. Over and again, The Thing and others of its ilk call for a response. Horror is then an interrogative genre that demands of its subjects, on screen and off, a reply. Is this some kind of joke?