When the film was originally released, theatergoers were given a packet of "Satan's Soul" seeds when they purchased their tickets. Each paper envelope (illustrated with the movie's logo) contained two seeds, which were, according to the instructions, supposed to provide protection "from the Black Magic of The Brotherhood of Satan". It is not known for certain if anything (hellish or otherwise) ever sprouted from the seeds.
The poem being read out loud as the man and his wife die is "Thanatopsis" by William Cullen Bryant.
The comic book that Tobey offers to K.T. is Adventures Into the Unknown #142 (August 1963)
There was also a novelization released around the time of the film, which was written by L.Q. Jones.