Card Trivia:Nightmare Horse
- This monster is a reference to the horse found in the 1781 oil painting The Nightmare by Anglo-Swiss artist Henry Fuseli. This painting shows a woman in deep sleep with her arms thrown below her, and with a demonic and apelike incubus crouched on her chest.
- The horse along with the incubus in the painting refer to the contemporary belief and folklore about nightmares.
- The "Nightmare" in this monster's name might be a pun on mare which is an adult female horse or other equine.
- This monster appears in the artwork of "Reaper on the Nightmare", due to being one of its Fusion Materials.
- Strangely, this card's text in its original TCG print in Pharaonic Guardian is "This monster can attack your opponent's Life Points directly even if there is a monster on your opponent's side of the field." "Servant of Catabolism", which debuted in the same TCG pack, says "This monster may attack your opponent's Life Points directly." in its original text. Despite being worded differently, both effects are identical.
