Lou Costello's practice of taking home props proved to be a major problem for the special effects crew. Some of the special effects shots required the sets and props to remain intact for shooting with, and without, the actors. Reportedly on one occasion when Lou removed a prop, it required two days of re-shooting for the special effects department.
Marjorie Reynolds was loaned from Paramount.
Harry Woolman as "Motorcycle Rider" and Walter Baldwin as "Bates" are in studio records/casting call lists, but they did not appear or were not identifiable in the movie.
The cost of the special effects made this the most expensive Bud Abbott and Lou Costello feature up to that time.
This would be the first Bud Abbott and Lou Costello feature directed by Charles Barton, who is generally regarded as their best director.
Three weeks into shooting, Lou Costello demanded that his role be switched with Bud Abbott's. When director Charles Barton explained that this was unreasonable, Costello walked off the set. The cast and crew frantically worked around him for the next two weeks, when Costello slipped back onto the set and completed the film. He never apologized or explained his behavior.
When Emily, the character played by Gale Sondergaard, meets the new occupants of the house, one of the women asks her "Didn't I see you in 'Rebecca'?". Sondergaard's character is made to look like Judith Anderson's character in the Alfred Hitchcock thriller Rebecca, and Sondergaard herself bears a striking physical resemblance to Anderson.
When this film was scheduled to be shot, Bud Abbott and Lou Costello were in the midst of one of their feuds, and were not speaking to each other. Consequently, the two have very few scenes where they appear together. They were also feuding when they began shooting Little Giant, which is why they also have few scenes together in that picture.
Writing in the Saturday Evening Post in 1949, Bud Abbott said this was his favorite film role, because for a change he was the butt of all the punishment, instead of Lou Costello.