Selman wanted to tip his hat to the Lego friend playsets by Lego-ifying Malibu Stacy, as seen on Lisa’s wall. “Our kids love the Lego friend playsets,” he says, “so it seemed cute that Lisa’s Malibu Stacy dolls would look like the Lego Friend designs.”
Bart’s giant super robot elicited shock and awe from Selman and Kelley. “We were stunned to receive pictures of an actual model from the Lego builders based on what we’d written in the script,” says Kelley, noting that their instructions were to imagine what would happen if a kid assembled a bunch of Lego sets, picked them up and smashed them on the ground before putting together a new creation using those big, half-destroyed chunks. “This is a real model. This thing would actually be able to walk around. I don’t know if it would actually be able to fire light sabers. They put a lot of work into it, and our animators put a lot of work into it, and it’s so above and beyond what Matt and I thought this would be. It’s one of the coolest things in the episode.” Adds Selman: “If you look closely, you can see that indeed there are pieces from Hobbit-hole, Spongebob, and Batmobile playsets in the robot. Also, for some reason, Bart pilots it from the crotch.”
The Simpsons team had been working on a Lego episode independently of The Lego Movie, and when the film came out in February, “I said, ‘Oh god, this movie’s really funny and the plot is similar to ours!'” recalls Kelley. “So I immediately texted Matt and said, ‘Go to the theater right now.’ And he went and saw it and said, ‘No, no, no, we’re fine.’ But it definitely felt like at the end of the episode, it was an appropriate time to say: ‘We realize that there might be a small similarity here.’ Also, we just wanted to have Emmet and Wildstyle in our episode because we were fans of the movie.” While the Simpsons‘ Lego world couldn’t be altered much at all because it was in the finishing stages of CGI, the writers were able to add those two cameos and Homer’s joke in the 2-D world. In addition, they edited out a few moments that felt too close to elements in the movie. “When Homer goes between dimensions, he used to go through a magical tunnel, and we lost it because there is that tunnel in the movie,” says Selman. A short construction scene was also left on the cutting room floor after they saw that Emmet was a construction worker and had a big construction-site scene.
The episode’s final joke — the camera pulling back on the neighborhood, country, world and solar system until we see the Lego claw hands folding up the Universe — was Selman’s nod to cult classic Time Bandits, even using the music from the movie. “I am the biggest Time Bandits weirdo in the world,” he says. “I thought: What if the so-called real world is actually part of a giant cosmic Lego set? I hope young people who see it will not think it is a reference to Men in Black, as the Men in Black ending was a twist on the ending to Time Bandits.” To settle on the age of the universe and the number of pieces (which is the number of atoms in the observable universe), Selman consulted with Simon Singh, the author of The Simpsons and Their Mathematical Secrets. “The fans would never forgive us, if we did not have the accurate number of plastic molecules in our Philip K. Dick-ian meta-universe.”