Rondo Hatton passed away before the film was released. Universal was so embarrassed by its shameless exploitation of Hatton's disfiguring illness (which led to his death) that it sold all rights to the finished film to "B" studio Producers Releasing Corporation (PRC). It's unlikely Universal would've given two thoughts to hurting anyone's feelings; more accurately, they were about to merge with International Pictures, and were ceasing production of B horror movies, so they sold the picture to PRC.
Rondo Hatton, who played the monstrous Creeper in this film and in House of Horrors (1946), was actually handsome as a young man, but later in life became disfigured by acromegaly, a form of gigantism brought about by unnaturally high levels of human growth hormone produced by a disease of the pituitary gland.
In England, the rating of H (Horrific) was created specifically for this film, and no one under 16 was allowed to see it.
Tristram Coffin, who appears briefly as a police lieutenant, doubles as the voice of the radio reporter.
Completed in November 1945, released by PRC a year later on October 1, 1946 (Rondo Hatton's final performance). This was a sequel to House of Horrors (1946), completed in September 1945. In between, Hatton shot The Spider Woman Strikes Back (1946) in October, all three features only seeing release after his death in February 1946. Hatton had first played The Creeper in the Sherlock Holmes feature The Pearl of Death (1944), unrelated to the two follow-ups.