The wraparound segment that introduces the three "Treehouse" segments also was a new animation challenge.
In that, aliens Kang and Kodos are reading from a live-action book. Omine said stop-animation was used to move the book, and the aliens' tentacles, frame by frame.
The Chiodo Brothers joined The Simpsons' Mike B. Anderson and Tom Klein for the book sequence.
"That tentacle is a little foam thing that they just bent," Omine said. "I wrote all the text, so there's actually a little extra story there for people if you go back and freeze frame and read what's in the book."
The most traditional segment of "Trehouse" for Omine was a satire of The Babadook called "The Pooka Dook." Marge reads to Maggie from a spooky pop-up book modeled after The Babadook.
"I wanted to be even more elaborate," Omine said. "It's less scary the first time you see the Pooka Dook and then when the book comes back it's much scarier."
The Simpsons ultimately hired the Korean studio DR Movie to animate the "Death Tome" segment. Omine combined the looks of existing anime characters to approximate what Homer, Lisa and others would look like in anime.
For example, "Our characters blink much more often," Omine told UPI in a recent Zoom interview.
A Westworld spoof turns The Simpsons into robot hosts in a theme park based on the series. The segment opens with a scene from the classic episode "Marge Vs. the Monorail," which was animated in standard definition in 1993.
Now, high definition characters interact with the monorail episode, but Omine changed the original scene from night to daytime to fit the "Simpsons World" story.
"The establishing shot of the monorail is a shot from the [original] show," Omine said.
Like in Westworld, the Homer host realizes he is a robot. Homer wakes robot versions of Marge, Bart, Lisa and Maggie to escape Simpsons World.
Their escape takes the Simpsons through robotic recreations of past episodes. Like Westworld, this also presents the Simpsons with an existential crisis.
"How would the characters feel if they woke up and realized they were part of this giant franchise?" Omine said.
"Once we started storyboarding it, then Matt would go, 'More,'" Omine said. "We'd come up with lists and lists and lists. Then he'd still say, 'More.'"
Scenes expanded to include more and more references to past episodes. For example, Homer picks one of many Lisa robots, each dressed in a different outfit, from one of Lisa's past episodes.
"When they actually lay it out, [animators] go, 'Oh, actually, we need more Lisas,'" Omine said. "So then you just start racking your brain. How many other Lisas are there? Are they recognizable?"
One difference between "Simpsons World" and Westworld is that the Simpsons robots are not anatomically correct
"People are not going into the park and abusing these robots in that way," Omine said.