Why did Pixar's Elio put up the worst numbers in the studio's history in its opening weekend? The reasons professionals give for the sci-fi family movie's paltry $35 million US global box-office earning vary. But if you ask the internet, there's a far simpler issue at play.

"Nobody wants the bean mouth style of character design," wrote one reader when commenting on a post-mortem of Elio's bombing by the website Cartoon Brew. "It feels lazy, overused, and unoriginal."

"The 3D CalArts 'bean mouth' style also just put a lot of people off," read a post on a Reddit thread about Elio's failure. "Doesn't matter how good the story is, many people hate that animation style."

The bean-mouth criticism is an opinion about Elio that's echoed across virtually every platform that allows comments: a one-to-one connection between character design and the audience's decision to stay home. 

More than that, it's become synonymous with an almost vitriolic hatred for a particular and supposedly ubiquitous art style. Animation journalist John Maher calls it a "pejorative and insult" that far outstrips the style's reach and misunderstands its origin.  

"It is a reflexive internet criticism," said Maher, the news director for Publishers Weekly. "People found a term that was snappy and catchy and easy to use. And so they hung onto it."

The terms "CalArts style," "bean mouth" and "thin-line animation," all have different origins and meanings, but they all generally refer to a drawing technique exemplified by thin line-work, simplified features and bean-shaped mouths and heads. 

When it comes to how the "CalArts style" name came to be — Maher and others often point to Ren & Stimpy creator John Kricfalusi. 

Starting in the early 2000s, Kricfalusi wrote blog posts criticizing a particular style of art and derivative mentality he believed came out of the California Institute of the Arts — an influential arts and animation school founded by Walt Disney and his brother, Roy, in 1961. 

His criticisms were pointedly about the style championed by Disney, then copied to diminishing returns — including in movies like Treasure Planet and The Iron Giant. 

Though the animation in those movies looks nothing like what most people today think of as the CalArts style, the name stuck. And as many graduates of the school became associated with shows and movies that shared a similar bean-mouth design — including Elio, which has a pair of CalArts alumni listed as directors — the two names came to describe a common gripe. 

"That phrase has become a shorthand for a more fair criticism. Which frankly is: 'Animation as innovation rather than animation as imitation,' " Maher said. "But to call it all CalArts is just so silly and reductive and inaccurate — just fundamentally inaccurate."

When asked if CalArts teaches the style, or even observes it in common use among students, Maija Burnett, the school's director of the Character Animation Program, says that's not the case. 

"Luckily, I can definitely dispel that," she said. "The results of the work from our program is extremely diverse. And so I do not think it typifies what comes from our programs at all."

She also says it's unlikely that Pixar chose that animation style because it's cheaper, noting that the studio does most of its animation in-house, developed over years through huge teams, so they wouldn't need to default to any particular style an outside studio would find easier to work with.

It's hard to say how pervasive the style is among Pixar movies. Typically only Luca, Turning Red and Elio have received the "bean-mouth" criticism. But Burnett says what people are likely identifying is an intentional technique studios employ. 

"Often, we can kind of tell like, 'Oh, yeah that seems like it's coming from Sony,' " she said, noting it's natural that Pixar would have a recognizable style because it's important to them both as a brand and as a studio.

She says there's also likely a reason certain elements of the style are more widely used today. 

TV series, for example, often rely on animation techniques that work with contemporary technologies — such as the 1920s "rubber-hose" style of Felix the Cat, the "flash" animation of the early 2000s seen in Canada's 6teen, or the simplified "limited animation" style of Hanna-Barbera, the studio behind The Flintstones that essentially birthed a movement of low-budget animation in the '60s and '70s.

As animation techniques progress, Burnett says they'll likely change again to fall in line with new technologies. She also notes that every art form and industry has eras where the output shares similar characteristics: from cubist paintings, to art deco architecture, to postmodern literature. 

The idea that the bean-mouth style is somehow more pervasive today might be related to nostalgia, she says, noting that the CalArts style was first identified around the time that social media became popular, making it one of the first animation trends to be subject to wider internet scrutiny.

Finding like minds to discuss the art you grew up with gives people something to bond over, she says, and so does being able to name and shame the style that seemingly replaced it.

But box-office analyst Paul Dergarabedian says the look of animated movies is rarely the most important factor in ticket sales, making it unlikely that's what sank Elio. 

"To me, that's a non-starter," he said, pointing to the Oscar-winning film Flow — animated with the free, open-source software Blender — as an example of how story trumps animation techniques. "That, to me, is like grasping at straws to find a reason that the movie didn't do it."

The more likely culprits, he says, include the movie's minimal marketing, its PG rating and a lack of franchise tie-ins. And the more competitive landscape for original stories makes the market for animated movies vastly more challenging than when Pixar's Monsters Inc. or the first three Toy Story movies premiered.

Maher agrees, and says the idea that fans suddenly abandoned Pixar over an animation technique is more depressing than believable. 

"That has nothing to do with thinking that it's like, a lesser work of art because of the shape of the character's mouth. Give me a break," he said.

"If that's really what we are condemning art for at this point — we don't like the style so we're not even going to bother to understand the substance — we're in trouble."