In the wise words of James Corden, there comes along a song every so often that defines a generation.
Doo doo doo doo doo doo.
The late-night TV host, carpool karaoke king and father of three young children was referring specifically, and wryly, to "Baby Shark," now the bloodthirstiest of earworms for some parents and meme lovers everywhere.
Insert shark hands here.
If you don't know what I'm talking about, you've been living inside a sea anemone since at least 2015. That's when an educational content brand in South Korea, Pinkfong, released its first shark video, later breaking the internet with a version mixing animation and two adorable human kids dancing out the story of a shark family, K-pop style, earning more than 2 billion views on YouTube.
If you still don't know what I'm talking about, you haven't spent enough time at summer camp or around a campfire, where singalong versions of said story with said gestures, akin to an old nursery rhyme with the same theme, have rocked on for decades.
Now, thanks to the #babysharkchallenge that has us all singing, doing our shark hands and sharing on social media, and thanks to piles of soft shark heads, toddler attire and other swag that includes singing plush toys and books, "Baby Shark" is a full-on craze, for bite-size fans anyway.
"Our toddler's shark video addiction is a huge issue in our household," said Columbus, Ohio, mom Kitty French. "At first it was a cute melody. Now it's an earworm that literally all of our parent friends understand."
Not all grown-ups are weary. If they were, would they continue to upload themselves in mashups and mixes, from R&B to Santa Claus? Can we do without the absolutely cutest home video of them all, the little girl begging Alexa to play her favorite shark jam, frustrated by the not-so-smart device's inability to understand? What about the Texas family so enamored they synchronized their blinking, blinding holiday yard lights to the snappy tune?
Some parents of special needs kids think "Baby Shark" has not only entertained but helped their young ones.
Holly Anderson is a Utah mother of four, including a 3-year-old son with autism and apraxia of speech. His autism therapist uses children's songs on YouTube to motivate him to sit still and was the first to show him "Baby Shark."
"He's overstimulated visually and usually won't watch any shows on TV or the iPad," Anderson said. "He has a very difficult time staying still, even for a moment, and usually spends his time running around in therapy. I'm honestly not sick of it yet since it's one of the only ways to get him calm after a meltdown."
The one he likes the most is by Pinkfong, she said. The company has put up more than one version. Other parents said their kids prefer versions of baby, mama, papa, grandma and grandpa shark from a content provider called Super Simple. There are many, many other offerings to choose from and many, many more millions of views than the jackpot scored by Pinkfong for its dance version.
Corden, host of "The Late Late Show with James Corden," isn't the only celebrity to take on baby shark madness. He enlisted Sophie Turner and Josh Groban to perform the song on air. Ellen DeGeneres put her spin on the song on her talk show as well and Simon Cowell's 4-year-old son popped up on the "X-Factor UK" as dancing cuteness ensued with singing kids accompanied by adults in shark suits for the opening of the grand final this year.
Bob Cunningham, an educator and senior adviser for the nonprofit consortium Understood.org, which supports parents of kids with learning and attention issues, sees several benefits to "Baby Shark."
"The song has a catchy rhythm and it uses silly sounds as well as colorful and cute animation," he said. "Also, both the music and the animation are predictable, with repeated words, phrases, colors and movements."
The combinations can capture and sustain attention even in children where attention isn't a strength, Cunningham said. The song and video also engage most of the senses simultaneously and combine language with music and movement, which can appeal to kids who struggle with any of those things when they are presented in isolation. For example, the movement can support less developed language and the music can offer support when movements are difficult, he said.
Clearly, other kid content can do the same, but "Baby Shark" ruled at Jason Simms' house, at least for a time.
Simms, who lives in Deep River, Connecticut, said his 14-month-old daughter Fionnuala first heard the song when she was 8 months old but has since tired of it, before her parents did, once her language comprehension skills began kicking in.
"It was one of the first things in life she directly expressed a preference for, so that's why we picked it for her Halloween costume," he said. "At the end of the Super Simple version, it says 'bye bye sharks' and that became how we say bye in our family. She now fusses when she hears it."
But there's plenty more fish in the "Baby Shark" sea.
A Montreal-based company, WowWee, has a Pinkfong license for North America to sell the shark family in plush toys that sing when tummies are squeezed, along with soft song cube versions. Available exclusively on Amazon on pre-order that guaranteed delivery in time for Christmas, they sold out in two and a half days earlier this month, said Davin Sufer, WowWee's chief technology officer.
Sufer would not disclose how many units were gobbled up at $19.99 each. More will be rolled out at a broader range of retailers come early 2019, along with new offerings. Third-party sellers who nabbed the toys are now offering them for more than $100 on Amazon.
The privately-held WowWee was already in talks with Pinkfong as far back as nearly a year ago when "Baby Shark" truly exploded, said Sufer, who has three kids of his own, including a 9-year-old daughter who came home from camp last summer singing the song before she knew his involvement.
"The tune itself has an addictive quality to it," he said. "You hear it once or twice and you hear yourself singing, doo doo doo doo doo doo. I could see maybe parents getting a little tired of it, but kids aren't."