According to writer David Gerrold, the episode is inspired by H.P. Lovecraft and includes many references.
The episode was recorded on October 24, 1986.
The case takes place in Arkham, making it Egon and Peter's second trip there. The first was in "The Collect Call of Cathulhu" when they visited Miskatonic University. Arkham is a fictional city located in Massachusetts as part of the Lovecraft Country created by H.P. Lovecraft.
Ray's line, "I think, but I shall never see a poem as lovely as a tree!" is the first two lines from Joyce Kilmer's poem "Trees" which first appeared in 1913.