Chase Novak’s diabolically entertaining new novel recalls Rosemary’s Baby. In it, a well-heeled Manhattan couple conceive a child in fraught circumstances. Result: horror. But instead of a baby gone monstrous, this time it’s the parents.

Breed starts out affably enough. Alex Twisden and Leslie Kramer live almost directly across Central Park from where the movie version of Rosemary’s Baby was set — in the neo-Gothic Dakota Apartments. Alex, a lawyer from a stuffy old family, hardly bothers to hide his sense of privilege. Although less haughty, Leslie meets Alex’s high standards thanks to her beauty and brains (she has a high-powered job in publishing). Alex wants an heir, and Leslie yearns to be a mom, but pregnancy remains elusive. In their frustration, they join a support group for couples in the same fix.

Then Alex and Leslie run into the Johnsons, a couple from the support group who have succeeded where the others failed: They have a baby. Never mind the husband’s feral appearance and erratic behavior. On his say-so, Alex and Leslie are soon en route to Slovenia, where for a hefty fee a certain Dr. Kis will work his magic on their behalf.

Back home after being injected by the eccentric Slovene, Alex and Leslie undergo profound changes. One day while visiting the Johnsons, Alex swipes from their refrigerator a Ziploc bag containing a dead rodent. Later, in private, “he takes his prize out of his pocket and devours the plump hamster in four quick bites. It is easily and without question the most delicious thing he has ever tasted.” For Leslie, the transformation is more benign, at least at first: She is pregnant.

Three children are born. One of them is so malformed that the doctors and nurses hide it away. The other two, Adam and Alice, are seemingly normal.

All this takes place in the first 60 pages. The remaining four-fifths of the novel pits Adam and Alice, now 10, against Alex and Leslie, whose love for their offspring is so bestial that they may literally act out that standard parental effusion, “I could eat you up.”

There are chases across Manhattan, with Central Park providing a refuge for a band of kids who are also products of the Kis method. Innocent bystanders are dragged in, notably Mr. Medoff, one of Adam’s teachers. When Adam escapes from his parents’ custody and shows up at Mr. Medoff’s apartment, the teacher would like to help but, being gay, faces an exquisite dilemma: By taking in this desperate fugitive, he will leave himself open to Lord knows what kind of accusations. And there is a raucous climax in and around the Metropolitan Museum of Art. Along with suspense and shocks, Novak delivers enough humor to make the mayhem palatable.

Three decades ago, Novak, also known as the Washington-born writer Scott Spencer, gave us Endless Love, a now-classic novel about youthful passion taken to excess. His most recent novel was the fine thriller Man in the Woods. Breed hews more closely to the recipe for its genre, but with triumphant effect. The best American horror novel since Scott Smith’s The Ruins, Breed is redolent of Roald Dahl at his creepy best.

Dennis Drabelle reviewed this book for The Washington Post.