| Episode Information
- "Mr. Simpson, I'm afraid you have a crayon lodged in your brain."
- ―A pharmaceutical researcher to Homer
- "An X-ray reveals that Homer has a crayon lodged in his brain that has been there since childhood. Upon removal of the crayon, Homer's IQ suddenly jumps to a very high level; he and Lisa form a great new bond, but when his way of life changes drastically he wonders whether removing the crayon was a good idea."
When the family visits the Sick, Twisted and Totally F***ed up Animation Festival, Homer discovers Animotion, a motion capture technology that enables a cartoon character to mimic a human's movements. He likes it so much that he invests the family's life savings in Animotion. The next day at work, Homer checks his stocks, the operator tells him that Animotion's stock is up by one. Homer shouts,"Yahoo!" and the operator tells him that Yahoo!'s stocks are up by six. Homer says,"Huh? What the hell is this crap?" and the operator tells him FOX's stocks are down by eight. The next day, Homer learns that the Animotion has gone into "super-duper" bankruptcy.
To earn the family's life savings money back, Homer takes a job at a medical testing center. During one experiment, the doctors find a crayon lodged in Homer's brain from when he was a child, which has been the cause of his life-long stupidity. After the crayon is removed, Homer's IQ goes up from 55 to 105 points, which allows him to form a bond with Lisa. Homer gives a speech at Springfield Elementary, where Nelson gives him a fake question, saying,"A-moron-says-what?" Homer responds with,"Not being a moron, I wouldn't know. However, [mumbles]" tricking Nelson into saying "what?" Homer says,"Ladies and gentlemen, I give you your moron!" And all the children 'ha-ha!' Nelson. Homer then writes a report on the nuclear plant's safety, which results in the plant being shut down, and the laying off of all employees.
Homer's friends, initially thrilled to have a smarter Homer around, quickly reject him, and a Homer model is even burned at Moe's Tavern, which he is not allowed in. Lisa tries to explain, with the aid of a graph, that as you get smarter, happiness decreases. Homer decides to put a crayon back in his brain, with the aid of Moe, who says he is an unlicensed surgeon, and describes the procedure as "the old Crayola oblongata". Homer arrives home his old, dumb, self, which initially disappoints Lisa. However, she finds a letter Homer wrote to her before the surgery, explaining that he now understands what it is like to be smart like her, and how much more he appreciates her because of this. When Homer comes into the living room eating a sandwich, Lisa runs up to hug him. Homer mistakes her for wanting his sandwich and pull away, then saying,"Oh, you want a hug." As they hug, Homer takes another bite of his sandwich and says,"Mmm... hug."
The episode was written by current show runner Al Jean and directed by supervising director Mike B. Anderson. Jean based the episode's plot on Flowers for Algernon, a novel which he had read in the 8th grade.
The claymation sequence seen in the cartoon Ned Flanders lets Rod and Todd watch - "The New Adventures of Gravey and Jobriath" - was produced by Chiodo Bros, Productions. The studio would later create other stop-motion segments in episodes such as, "The Girl Who Slept Too Little", "Angry Dad: The Movie" and "Ned 'n' Edna's Blend Agenda" 
The episode has received positive reviews from critics. IGN has deemed the episode "a classic."  AOL Television listed the episode at #18 on their list of the "The Simpsons' Best Episodes", which detailed the top twenty episodes of the series. About.com gave an overwhelmingly positive review and summed up, "The storyline was solid and didn't go off track" and gave praise to the episode's "clever" comedy for harkening back to the show's glory days. Conversely, DVD Talk had less positive opinion on the episode. They criticized the episode as "unoriginal" due to similarities to the third season episode, "Bart's Friend Falls in Love" and concluded, "the show has a moderately rehashed feel, so don't expect a lot of thrills." However, they did give praise to some comedic aspects of the show.
Since airing, the episode has received a similar reception from fans of the series. On No Homers, a fan forum dedicated to Simpsons discussion, the episode received a 5/5 majority poll rating. Many fans lauded the episode, with some naming it, "the strongest episode of Season 12" and "One of the best post-classic episodes", with particular praise going to the last act. Despite this praise, not all fans shared mutual critiques and the episode is said to have divided fan opinion. Some fans were upset with the episode overwriting the continuity established in "Lisa the Simpson", while others simply consider the episode "overrated."
The episode won the series a Primetime Emmy Award for Outstanding Animated Program (for Programming Less Than One Hour), making it the eleventh win for the series. The episode was nominated for various other awards, but lost to the Futurama episode, "The Luck of the Fryrish".
- Chiodo Bros, Productions Official Facebook Page - status detailing work produced for "The Simpsons", notably the "Ned 'n' Edna's Blend Agenda" stop-motion segment
- Associated Press. "This week's top shows", p. A12.
- IGN.com - Cindy White, 2009-08-18 - "The Simpsons: The Complete Twelfth Season DVD Review, A comic-book theme makes this box set a worthy addition to your collection."
- AOL Television - "'The Simpsons' Best Episodes: No. 20 - 16"
- About.com - Animated TV Guide - By Nancy Basile - "'The Simpsons' Episode Guide - Season Twelve"
- DVD Talk - Reviewed by Colin Jacobson (September 2, 2009) - "The Simpsons: The Complete Twelfth Season (2000)"
- No Homers - Forum/Simpsons Episode Discussion - "R&R HOMR"