Mom And Dad, in which suburban parents Brent (Nicolas Cage) and Kendall (Selma Blair) are brain-zapped into wanting to murder their two children. Picture: YouTube.com

Washington - In 1812, brothers Jacob and Wilhelm Grimm published the first edition of Children's And Household Tales, a scholarly history of old stories that included a sleeper hit called Snow White, where a young beauty is hunted by her own mother who wants to eat her lungs and liver with salt.

Critics savaged the book, one Berlin professor decrying these ancient tales of child-murder as "the most pathetic and tasteless material imaginable." The Brothers Grimm needed cash. So Wilhelm sanitized their next editions and swapped Snow White's mother for a step-mom, a tweak that helped make them famous.

A parent killing their own child is our most grotesque taboo. Scandalized audiences claim these stories are repellent, but they've fascinated us for millennia, a dark blood that's pumped through our legends ever since Abraham tied Isaac to an altar and hoped for a literal deus ex machine reprieve. 

The Bible surfaces again in Sophie's Choice when the Nazi who forces Meryl Streep to pick which of her two children will be gassed at Auschwitz has the nerve to quote Jesus: "Did he not say, 'Suffer the little children to come unto me?' " More recently, tabloids made a fortune accusing mother Patsy Ramsey of bludgeoning her six-year-old pageant queen daughter, JonBenét.

"There's a great history of stuff like this," writer-director Brian Taylor says, nodding to the ancient classics. "But I don't know if it's normally played for laughs." The co-writer/director of the slapstick-thriller Crank franchise is known for being outrageous. He made Jason Statham electrocute his tongue with a jumper cable.

Yet, when he pitched his new horror-comedy, Mom And Dad, in which suburban parents Brent (Nicolas Cage) and Kendall (Selma Blair) are brain-zapped into wanting to murder their two children - "I'm a parent, so it's kind of an obvious idea" - his agents tried to talk him out of it. A satire in which parents chase after their kids with baseball bats and broken whiskey bottles? Just the log line frightened people. Still, when Taylor described his script to friends, they'd grin and say, "Oh, I'd see that movie. I want to kill my kid 10 times a day."

"With adults, there's nothing you can see today that's taboo," Taylor says. In his films, grown-ups are stabbed, shot, poisoned, incinerated and impaled - and audiences cackle. "With kids, there is a line where, if you cross it, the audience is never coming back."

His character Kendall would agree. Mom And Dad opens with the housewife mainlining coffee as a newscaster on the kitchen TV chirps about the town's brainwashed Patient Zero ditching her kid in front of a speeding train. "Before breakfast?" Kendall sighs. When her husband and young son, Josh (Zackary Arthur), re-enact the death with a plastic truck and squeeze bottle of ketchup, she growls, "So not funny."

Something seems to be shifting in the zeitgeist. After more than a decade of hollow violence in which superheroes raze battlefields of generic CG goons, filmmakers are looking for a way to make their wounds hurt. In May, Yorgos Lanthimos scored a Cannes Palme D'Or nomination for The Killing Of A Sacred Deer, a wicked morality play in which Colin Farrell is ordered to murder one family member to save the others. Like Sophie, he can choose. But instead of breaking into sobs, he calmly debates whom to kill. His son is good at math, but his daughter is excellent at literature. Eventually, he asks a co-worker, "Which would you say is the best?"

The sacred deer in the title is a nod to the myth of King Agamemnon, who accidentally kills one of the goddess Artemis' stags and, as punishment, is forced to decide between slaying his daughter Iphigenia, or flubbing the Trojan War. He chooses to murder the girl, spilling blood that will stain generations of his line.

Taylor's toughest critic, his son, has seen Mom And Dad twice. "The first thing he said was, 'Dad, what's wrong with you?' " Taylor laughs. "He's in college - he's much harder to catch."