The episode had a very troubled production, taking a year to complete from the beginning of production in February 1991 until it aired a year later in February 1992. The story originated in 1990 when
Bob Camp developed the idea of a story called ''Stimpy's Inventions'' in which Ren serves as an unwilling guinea pig for Stimpy's impractical inventions.
John Kricfalusi was greatly taken with Camp's idea. Camp later explained that Kricfalusi was deeply invested in the idea, obsessively refining each detail to an extreme degree until he felt it was perfect. Kricfalusi altered the story's direction after suggesting to Camp that Ren should experience a complete breakdown, prompting Stimpy to create the Happy Helmet, an invention intended to cure him, but enslaves him and focused on his struggle for freedom.
Writing (pictured in 2015) conceptualized the story of "Stimpy's Invention", impressing Kricfalusi.|alt=A man with a short white beard wearing glasses and a black-and-white bucket hat, grins at the camera as he's holding a pen in front of Ren and Stimpy merchandise. The executives wanted to have the scenes where Stimpy uses a duck as a tool, Ren whacks Stimpy with a folded newspaper, and Ren grins so wildly "that the top of his head separated from his lower jaw". Some of the more extreme elements of the story were removed, despite that much of the material that the executives objected to was not removed and went to air anyway. In a 2008 interview, Kricfalusi stated he had to strongly persuade producer
Vanessa Coffey to approve production on "Stimpy's Invention", as the team lost a month because of issues beyond their control. He mentioned that both "
Space Madness" and "Stimpy's Invention" were initially rejected by Nickelodeon before convincing them otherwise—ironically, they went on to become the show's most popular episodes.
Vincent Waller stated that the network executives disliked Stimpy's use of a duck to solder together the Happy Helmet due to concerns that it might inspire children to imitate using ducks as tools and wanted Stimpy to use a
woodpecker instead. According to Waller, there were concerns that the scene was too painful for the duck, suggesting that having its head interact with hard metal in such a way could cause harm. Kricfalusi sent out a memo that stated the animation team was going to draw a duck as he recalled: "I just sent them back a note saying, 'No.'" In interviews, Kricfalusi stated that the episode faced significant delays due to prolonged approval processes. When the storyboard was originally reviewed, executives didn't understand it and wanted it scrapped immediately. He said he had to plead with Coffey, producer of
The Ren & Stimpy Show, to move forward with it. Despite Coffey approving the story outline, Kricfalusi noted that
Will McRobb was against the concept since its beginning, expressing concern over a cartoon about mind control for children—an objection Kricfalusi claimed not to understand. Coffey admitted to having disagreements with Kricfalusi over the story's content, but denied Kricfalusi's claim that she wanted to veto the episode. Several scenes were censored by the network executives, most notably a scene where Ren, under the control of the Happy Helmet, submissively licks Stimpy, which did not make it past the storyboard phase, owing to its homoerotic elements.
Storyboarding The storyboard phase of the episode started in late 1990 and was finished by late February 1991. The animators who worked on the episode have stated that it was Kricfalusi's obsessive perfectionism and micro-management leadership style that delayed the production. The animators who worked on "Stimpy's Invention" have stated in various interviews that the network executives censored several scenes contained in the storyboard phase, most notably the licking scene, but afterward were content to let production proceed after it started in February 1991. "Stimpy's Invention" was scheduled to premiere in October 1991, but did not premiere until February 1992 due to the production delays. Camp described the production as extremely demanding, reflecting that the team exhausted themselves trying to perfect it. Constant revisions and fine-tuning prevented the episode from finishing by its deadline. According to Camp, the episode was a rare blend of his own drawings and Kricfalusi's dedication, with the latter pushing everyone relentlessly in pursuit of perfection.
Animation Kricfalusi's insistence on redrawing many of the scenes himself greatly hindered production. One scene, where Stimpy presents his "Stay-Put Socks" to Ren, took an entire month to complete as Kricfalusi kept changing his mind about the color of the box that held the socks, despite the box being shown for only a few seconds. The scene's painter, Teale Wang, painted 50 different versions of the box in various colors and shades until Kricfalusi finally chose Wang's first painting of the box. Wang reported that she felt that Kricfalusi was even then not pleased with the coloring of the box. Likewise, another animator, David Koenigsberg, recalled that Kricfalusi would explode in anger at him over his coloring of the Happy Helmet and that it seemed that he could never quite color the Happy Helmet in a manner that was satisfactory to Kricfalusi. Koenigsberg recalled an incident in which Kricfalusi stormed into the workplace, angrily reprimanded him in front of others, and left in a rage. According to Koenigsberg, the outburst appeared entirely serious, leaving him confused about the reason for Kricfalusi's anger until fellow artist
Chris Reccardi remarked that such treatment was a common experience among the staff. Animator Mark Kausler, who drew the scene where Ren and Stimpy dance and the scene where Ren used a hammer to smash his head, stated that Kricfalusi was "not an easy director to please" and that "he didn't always know what he was looking for". For the dance Ren and Stimpy perform to
Happy Happy Joy Joy, in which they repeatedly rub their buttocks against each other, Kausler drew five different versions where Stimpy's buttocks grew progressively more inflated with each drawing. The most extreme version of Stimpy's bloated buttocks was rejected by Kricfalusi as too inappropriate for even his own sense of humor. Kricfalusi then changed his mind several weeks later and chose that version for the broadcast version.
Frequent delays 's studio,
Spümcø, under his supervision. The episode took a year to complete due to Kricfalusi's perfectionism and constant revisions.|alt=A man with fluffy short hair wearing glasses holds a duck towards his ear for a humorous photo. The production on "Stimpy's Invention" was so far behind in August–September 1991 that Carbunkle Cartoons in
Vancouver, that had been hired as a subcontractor for the animation, were forced to temporarily fire much of their staff as there was not enough material arriving from California to justify paying for a full staff. The scene where Ren, after having the Happy Helmet placed on his head, attempts to resist the effect and goes through a series of contorted facial expressions which show how difficult it is for him to smile, was especially onerous and difficult to draw. The task of illustrating the scene was assigned to Kelly Armstrong, the co-boss of Carbunkle and wife of
Bob Jaques, who impressed the other animators with her ability to illustrate such a dramatic transformation. Armstrong recalled animating Ren in the scene as particularly complex, with the character staggering, transitioning between two poses, and delivering dialogue simultaneously. Due to its difficulty, the mouth movements were animated in one sequence but "pinned" onto the head using a radically staggered order—all while matching the exaggerated motion of Ren. Much of production on "Stimpy's Invention" was done at
Spümcø in
Los Angeles under the watchful eyes of Kricfalusi. To the considerable annoyance of the other cartoonists who worked on the episode, Kricfalusi started to personally redraw much of the episode himself in October 1991, at a time when the episode was already supposed to have been aired. Koenigsberg stated that Kricfalusi had gone "a little bit nuts" by the fall of 1991 as he started to redraw scenes that already been sent to the Carbunkle studio, a practice that brought production to "a complete halt". Animator Christine Danzo stated that Kricfalusi at one point took the entire draft of the episode, locked it in his office, and refused to "let it out until he had gone through the entire show and had it the way he wanted". By November 1991, Howard Baker had resigned as the overseas supervisor, and Jaques was hired to go to the Philippines to oversee the inking of the episode by Fil-Cartoons at
Manila. Jaques, who disliked overseeing production in various Asian studios, whose poorly paid cartoonists had a level of craftsmanship not up to American standards, at first refused Kricfalusi's request to work as the overseas supervisor. Jaques saw the animation drafts of "
Fire Dogs" being vandalized by the staff of the Fil-Cartoons studio. The version of "Fire Dogs" that premiered in 1991 was shorter than intended due to production problems, as much of the footage had been vandalized beyond repair. Jaques was fond of his work on this episode and did not want the episode to get ruined the same way much of "Fire Dogs" had been ruined. When Jaques arrived in Manila in November 1991, he reported that much of the footage had been ruined due to incompetence, and he had to redo much of the episode himself using the original pencil drawings. Jaques called Fil-Cartoons "the cheapest [expletive] studio I've ever had the displeasure to work with". Animation historian Thad Komorowski wrote that Fil-Cartoons was the animation equivalent of a
sweatshop as many of the Fil-Cartoons cartoonists slept outside of the studio as they were unable to pay rent owing to their extremely low wages and the studio had no toilet paper in its washrooms out of the fear that the employees might steal it; he compared its performance unfavorably to
Lacewood Productions, another animation studio they hired with similarly abysmal working conditions and performance, though Kricfalusi didn't disapprove of its work. Jaques reported that the Filipino cartoonists of Fil-Cartoons were inept and that many of the visual flaws in "Stimpy's Invention" were due to their poor workmanship. Jaques described an incident where he discovered that a camera move on an exposure sheet was altered from a three-frame move to an eleven-frame move. When he questioned the checker about the change, the response was that a three-frame camera move wasn't possible—an assumption Jaques attributed to poor training. He emphasized that these misconceptions affected the animation process, stating that skilled animators can control nearly any aspect of a frame when they understand the medium properly. Owing to the demands from the network to have the episode finally finished, Jaques had several scenes of "Stimpy's Invention" discarded and only chose to focus on having the staff of Fil-Cartoons ink in and paint the scenes that he deemed essential for the story. To save time, Jaques used the workprint rather than the negative for the scene where Ren cleans Stimpy's filthy underwear, which was the reason for the dirt lines that appeared in the final version. Throughout November and December 1991, the Fil-Cartoons staff painted and inked in "Stimpy's Invention". Jaques reported that the cartoonists of Fil-Cartoons sabotaged much of the drawings of "Stimpy's Invention" out of anger as he showed them animation methods superior to their own. The scene where Stimpy has an epiphany and says, "I must use my gift of invention to save Ren!" had to be reshot in the United States as it was intentionally damaged in the Philippines. Jaques stated that Fil-Cartoons disregarded his instructions by altering the animation, despite being specifically told not to make any changes. The problems with Fil-Cartoons in the first season led to the work of inking in
The Ren & Stimpy Show episodes being subcontracted out to the
Rough Draft Korea studio in South Korea for the second season. The frequent delays on "Stimpy's Invention" led Nickelodeon to present it as a "lost episode" of
The Ren & Stimpy Show when it aired on February 23, 1992. ==Reception==