Faced with mortgage debts, Professor Nathaniel Billings (Boris Karloff) sells his 18th-century tavern to Winnie Layden (Jeff Donnell), who plans to turn it into a hotel. Billings stipulates as a condition of sale that he is able to continue working in a laboratory in the basement. His housekeeper Amelia Jones (Maude Eburne) and hired hand Ebenezer (George McKay) also continue to work in the inn. Layden is initially unaware of the nature of Billings's experiments in the basement laboratory: he is attempting to use electricity to create a race of superhumans to help the war effort. Layden's ex-husband Bill (Larry Parks) is against the sale, but is too late to stop it, and decides to stay on at the inn for a few days.
One night at dinner, the residents hear the sounds of a ghost. Bill suspects that this is part of a plan to scare the new owner away. While investigating, Bill discovers in the basement the dead body of travelling salesman Johnson (Eddie Laughton), an experiment subject who died shortly after the sale. He reports this discovery to the local sheriff Dr Arthur Lorentz (Peter Lorre). After making inquiries, Lorentz realises the potential for profit and decides to work with Billings on a subsequent experiment. Their initial plan is to use Bill as a test subject, but this proves unsuccessful, so they turn their attention to Maxie, a visiting powder puff salesman (Maxie Rosenbloom).
Before the experiments can begin, one of the inn's guests is murdered. Billings and Lorentz see the primary suspect as another guest, J. Gilbert Brampton (Don Beddoe), but the police officers who set out to investigate are intercepted on the way. Maxie scares away an intruder known as "Jo-Jo" (Frank Puglia), who is intending to steal Billings's equipment. Billings and Lorentz decide to begin their experiment on Maxie so that they can use him to stop "Jo-Jo" from blowing up a nearby munitions plant. Meanwhile, Brampton informs Winnie and Bill that he is visiting as a representative of the Historical Society of America, who are interested in buying the inn.
When the police officers eventually arrive, they arrest the housekeeper and Ebenezer for the murders. The dead bodies come back to life, having apparently been in a state of suspended animation. The police officers decide to send the rest of the house's inhabitants to the Idlewild Sanatorium, a local psychiatric institution.Boris Karloff as Prof. Nathaniel Billings
Peter Lorre as Dr. Lorentz
"Slapsie" Maxie Rosenbloom as Maxie, the Powder Puff Salesman
Larry Parks as Bill Layden
Miss Jeff Donnell as Winnie Slade (as Miss Jeff Donnell)
Maude Eburne as Amelia Jones
Don Beddoe as J. Gilbert Brampton
George McKay as Ebenezer
Frank Puglia as Silvio Bacigalupi, the Italian Escaped-POW
Eddie Laughton as Mr. Johnson
Frank Sully as Police Officer Starrett
James Morton as Trooper Frank Quincy
Frank Mitchell as Jo-Jo, the Human Bomb
The Boogie Man Will Get You was the final film that Boris Karloff made under his contract with Columbia, and the studio were hoping to build on the success of the Broadway play Arsenic and Old Lace, which Karloff was appearing in at the time. Production of the film took place while the play was on hiatus in summer 1942. There are many similarities between the film and Arsenic and Old Lace, including the presence of eccentric characters and the premise of dead bodies in the basement. As previously with the films he made with Columbia, Karloff was cast in the role of a "mad scientist", as he had been in The Man They Could Not Hang (1939), Before I Hang (1940), The Man With Nine Lives (1940) and The Devil Commands (1941).
The screenplay was written by Edwin Blum in four weeks, based on a story by Hal Fimberg and Robert B. Hunt, adapted by Paul Gangelin. Although the film is a comedy-horror, Blum described the studio's aims as creating a "goose pimple" film; Blum explained that he "was and still [is] incapable of writing a straight horror film". Before filming began, Jack Fier had been named as the producer, but Colbert Clark took over from him.
Columbia planned a publicity campaign to promote the film, polling film critics to compile a list of the ten best on-screen villains. The studio assumed that Karloff and Lorre would come high on the list, but the top three were all Disney characters: the witch from Snow White and the Seven Dwarfs, the wolf from Three Little Pigs and the cat from Pinocchio. The studio consequently abandoned this publicity idea.
The Boogie Man Will Get You was released in October 1942 to a mixed critical reception. A Variety reviewer commented positively on the film, describing it as a "screwball comedy" offering "hearty laughs". According to a reviewer in Kinematograph Weekly, however, the madness of the characters was "a little too studio to promote spontaneous thrills or laughter".Writing in the New York Daily News, Kate Cameron stated that "frightening people in theatres takes more ingenuity and adroitness than the authors of this screenplay put into it". The Monthly Film Bulletin found the film was "ably produced and directed" and that Karloff and Lorre "manage to sustain the appearance of mental unbalance well" while stating that the film was "a lot of nonsense with a certain amount of humor, bur rather too long-drawn-out."