Baby Shark takes a bite out of the UK Top 40 charts
It's not on the Radio 1 or 1Xtra playlists, but if you asked someone under 10 they'd probably say Baby Shark should be.
And this week, the children's song joins the likes of Ariana Grande, Drake and Calvin Harris in the UK Top 40.
It's actually been around since 2007, but a 2016 cover of the song went viral in August this year.
A video of the song, by YouTube channel Pinkfong, has been watched more than 1.6 billion times.
These views, and people listening on streaming services, has this week pushed the song into the charts.
Baby Shark has entered the UK Official Charts at number 37 - just above This Is Me by Keala Settle and I Like It by Cardi B.
'Only four plays a day'
Baby Shark has been driving Holly Leist, who's mum to six-year-old Isla, mad.
She's limited the song to just four plays a day in her house.
"My kids love it, they love doing the dance, they love singing it and it's very, very catchy," says Holly.
"They've been to lots of parties where they all run around singing it, doing the dance."
And like all the best viral hits, Baby Shark has also sparked a dance craze.
It's rare for viral hits to break out from internet fame and crack the UK charts, but there's something special about the Baby Shark Dance.
'Any country can relate to it'
Songwriter Jin Jin, who has written hits for Clean Bandit, Jess Glynne and Raye (among others) says the song contains key elements of good songwriting.
"A pop song definitely needs a big hook. That's the most important thing," she tells Newsbeat.
"It's got the repetition, and the 'do do do do do' is a global, international language. Any country or language can relate to that."
She also praises the simplicity of the song and says that's something professional songwriters aim for in their work.
"It's super simple. Often when I'm writing we come up with an idea, we throw everything at it and then strip it back," she says.
"We take out as much as we can to make sure the song can still stand at the end of it."
Is it safe to get back in the water?
Jin Jin is currently writing in Ibiza with Oliver Heldens, alongside other songwriters such as Raye and Kah-Lo.
She says she plans to start their next writing session with a little bit of Baby Shark.
"I'll be like 'Guys, this is what we need to aim for today'," she laughs.
But there's a sinister side to the song as well.
The original version of the song featured extra verses about a swimmer who has his leg bitten off, tries to dial the emergency services and tragically bleeds to death.