Based on the Ray Bradbury short story "Usher II" also known as "Carnival of Madness". This story was first published in Thrilling Wonder Stories (April 1950).

Bigelow: Is it everything you wanted, Mr. Stendahl?
Stendahl: Yes.
Bigelow: Is it desolate and terrible?
Stendahl: Very terrible.
Bigelow: The walls are bleak?
Stendahl: Amazingly so.
Bigelow: The sedge, we dyed it, you know. Is it properly hideous?
Stendahl: It's beautiful.

Stendahl: There's always a minority afraid of something, and a great majority afraid of the past, afraid of the future, afraid of themselves.

Garrett: Now suppose you tell me about this place, Mr. Stendahl.
Stendahl: It's a haunted castle, if you like.
Garrett: I don't like, Mr. Stendahl. I don't like.

Stendhal: In this house, copper bats fly in make-believe attics. Brass rats scuttle in plastic cellars. Robot skeletons rattle in dreary closets.
Garrett: Robot skeletons?
Stendhal: Vampires, wolves, phantoms. Done with chemicals and ingenuity.

Garrett: Mr. Stendahl, what exactly is going on here?
Stendahl: Murder.
Garrett: Murder?
Stendahl: Murder most foul!

Garrett: What are you doing?
Stendahl: I'm being ironic. Never interrupt a man when he's being ironic. It's not polite.

Changes in the short story:

* The short story is set on Mars. No mention is made of Mars or the censors' recent arrival in the episode.
* Due to budgetary constraints, an android witch kills Garrett, rather than a sophisticated robot ape.
* Also due to budgetary constraints, Stendahl's collection of androids only includes human figures from Poe's story. In the short story, he uses all manner of fantastical creatures: Santa Claus, Tweedledee and Tweedledum, giant mice, and so on.
* Finally, due to budgetary constraints, Stendahl and Pike simply ride away from the House of Usher. In the short story, the building collapses into the ground, emulating the end of Poe's Fall of the House of Usher.