In demonology, Marchosias is a great and mighty Marquis of Hell, commanding thirty legions of demons.
Adam Tsekhman was extremely excited when he first read the script: "Fortunately, I am a dog person, so I was very eager to play around with the doggie. It was great. I'm always sort of eager to lean into the comedy, so when the opportunity arises, I'm very excited to go down that road."
Gary's story of how he acquired "Gary Junior II" is based on Gremlins (1984). Gremlins director Joe Dante directed Night of the Hawk (2016).
The majority of the episode is set inside the Waverider due to a malfunction caused by the Loom of Fate. That said, despite the lack of a different setting or costumes, the episode makes extensive use of CGI with both the Loom of Fate sequence and the hellhound Marchosias (and a few other small moments here and there), suggesting that not as much money is being saved.
While Adam Tsekhman stopped short of calling it a bottle episode ("I'm not sure about the finances of the episode," he joked), he admitted that sometimes, it's the little things you enjoy the most - like a dog.