Read more from Slate's Summer Movies special issue.
Sometimes the evil-kiddie movie seeks to make a big point about the world we're leaving our kids. In Who Can Kill a Child? this takes the form of high-flown, not entirely coherent moralizing: The film starts with eight minutes of footage of children killed in the Holocaust, Vietnam, and African famines. Children of the Corn is partially a treatise on the deforming effects of religious fundamentalism—the evil kids take the Bible as their guiding text and claim direct communication with a bloodthirsty God. And Cold War-era anxieties about nuclear annihilation reverberate through The Omen, with its mixture of politics and the apocalyptic.
The evil-kiddie movie has been around long enough that new specimens must work hard to distinguish themselves from what's come before. In Orphan, there is an outlandish plot twist in which it's revealed that Esther isn't at all what she seems. (Skip this parenthetical to avoid the spoiler: She is, according to online reports, a midget ex-prostitute masquerading as an adolescent.) Far subtler are the variations that writer-director George Ratliff brings to the genre in 2007's Joshua. Ratliff, who made the fantastic documentary Hell House, knows about disturbing adolescents. Like Rhoda in The Bad Seed, Joshua Cairn is a wealthy, permanent-pressed overachiever who plays the piano constantly, a hobby that telegraphs both his precocity and creepy inward absorption. Joshua's means of destruction, unlike Rhoda's, are largely passive-aggressive: He exploits his parents' insecurities and weaknesses of character with virtuoso finesse, growing so expert at pushing their buttons that he drives them to behavior more unhinged than any of his own. In one of the most frightening scenes, he sends his mother into a nervous breakdown just by playing hide-and-seek very, very well.
While the moral calibration of other evil-kiddie movies puts a premium on the wholeness of the family, Joshua narrates a family's disintegration with a cold, merciless eye. "You don't have to love me," Joshua tells his dad early on. "It's not a rule." First he calls into question the basic premise of a family—because of blood, we love one another unconditionally—and then he goes about dismantling it, term by term, until his mother is in a mental home and his father's just some paranoid guy he shares an apartment with. Here is a villain more readily imaginable, and therefore much scarier, than any Armageddon-prophesying hell spawn, backwoods scythe wielder, or pigtailed death merchant: a 9-year-old deconstructionist.