The interior of the Brewster trailer - Unit #3 - is the set that had been built for the MGM movie The Long, Long Trailer (1954). The exterior of the trailer however is not the same New Moon model.
The alien brain was created by special effects artist Ivyl Burks and used $3,300 of neon lights to create the glowing effect.
The film was based on The Egg, an unpublished story by Tom Filer involving a girl with polio that was significantly different than the film.
This was one of director Jack Arnold's (along with producer William Alland) final science fiction features. This one was produced at Paramount instead of their home studio at Universal.
The daughter of a wildcat oil driller, Peggy Webber commenced her career at age two and a half, performing during intermissions in silent movie theaters. She started working in radio at age 11; by 18, she was writing, producing and directing early television shows; at 21, she won the award that was later known as the Emmy for her drama anthology series Treasures of Literature. Among her many thousands of radio credits, workhorse Webber appeared in over 100 Dragnet programs, playing Ma Friday and many other characters.