The 33rd installment of โ€œThe Simpsonsโ€ annual ‘Treehouse of Horror’ series was an ambitious one. Animation director Rob Oliver managed to bring three ghostly classics into the Simpsonverse, turning โ€œWestworld,โ€ โ€œThe Babadookโ€ and โ€œDeath Noteโ€ into Simpsonworld, the Pookadook and Death Tome. โ€œIt was taxing,โ€ Oliver said, but the work paid off โ€” the episode earned an Emmy nomination, making it the fourth Treehouse special to be nominated for a Primetime Emmy Award.

For Variety‘s “Making a Scene,” presented by HBO, Oliver and โ€œSimpsons’s” consulting producer David Silverman broke down their process of creating this year’s special. “I was extremely nervous. People had wanted it for so long that it could have easily been a swing and a miss,โ€ Oliver said.

Creating โ€œSimpsonsโ€ episode โ€œDeath Noteโ€ style, Oliver and his team hired a Korean animation studio that worked on the original 2006 โ€œDeath Noteโ€ to animate the entire Death Tome segment. โ€œWe would have botched it,โ€ Oliver said. โ€œSo, Iโ€™m glad they took it from us.โ€ The segment reimagined all characters from Marge to Jailbird.

For the spoof of HBOโ€™s โ€œWestworld,โ€ the team perused the vast library of โ€œSimpsonsโ€ lore and aggregated a huge number of iconic references all throughout Simpsonworld. Starting with the monorail, Oliver and Silverman took from Season 4โ€™s โ€œMarge vs. the Monorailโ€ episode. To make it look exactly like the original, the animation team traced over scenes from the orginal footage and then matched all the old and new colors by filtering them together. In addition, the team had to work around the difference in aspect ratios, which have changed from the boxier 4:3 to the wider 16:9 format. They managed to hide numerous other โ€œfan nuggets” in the foreground and background of the segment, from the classic Canyonero jingle to Homer skipping through the Land of Chocolate.

When it comes to making an installment of ‘Treehouse of Horror,’ the creation process is much different than any regular โ€œSimpsonsโ€ episode. Oliver explained that from script to air, these Halloween specials take about a year to create, compared to a normal episode which takes about nine months. While not quite as long as making a feature film, this year-long process gives animators and producers a chance to test their strengths.

โ€œYou learn to be a little bit more nimble and I think I learned how to follow my instincts better,โ€ said Silverman.

As a yearly feat, thereโ€™s little to no downtime from making one special to the next, which means Oliver had only a smidge of time to appreciate his teamโ€™s work on ‘Treehouse of Horror XXXIII.’ He said, โ€œThe day after this nominated Halloween episode aired, I started working on next yearโ€™s Halloween episode.โ€