Jeryl Prescott is the first actor to portray " Madame Xanadu" for a live-action DCU adaptation. Matt Wagner and Neil Gaiman wrote adventures for "Madame Xanadu" to reveal she is more than just a tarot card reader within the Vertigo comics line from DC. The original appearance for "Madame Xanadu" was in the pages of "Doorway to Nightmare 1" (February 1978) by Michael William Kaluta-David Michelinie-and Val Mayerick.
Swamp Thing made his comic book debut back in 1971 and has maintained his popularity as a stalwart of the DCU. The original Swamp Thing appearance was in "House of Secrets 92" (July 1971) created by Len Wein and Bernie Wrightson.
In Abby Arcane's first scene in this episode, she is speaking French; Crystal Reed does not actually speak French and has previously stated that she has a hard time remembering the French lines because of their unfamiliarity.
When Alec Holland said that he had seen an alien autopsy once, but he was pretty sure it was faked, he is likely referring to The Alien Autopsy (1995).