What do Baby Shark, the Harlem Shake, and Gangnam Style have in common?
Overplayed? Annoying? That's up to you.
But there's no doubt they all went viral on YouTube, which is now 20 years old.
It's the platform where 2.5 billion people log in monthly to pass the time, be entertained, and sometimes learn something.
It's also been life-changing for some of its breakout stars, like Charlie.
You might not recognize him now, but millions worldwide have watched him as a baby, biting his big brother's fingers.
That's because he's the star of Charlie Bit My Finger.
"It was never not a part of my life; it's always been there," says Charlie, now 18, to BBC Newsbeat.
The 55-second clip has had almost 900 million views since it was uploaded in 2007. Charlie says he can't remember the moment, filmed when he was "about one" and sitting on Harry's lap.
He says the clip's success has made life "easier" and helped him get to university, where he now studies law.
His dad, Howard Davies-Carr, previously told Newsbeat the family had made an estimated £1,000,000 from the video over the years.
The video was sold as a non-fungible token, or NFT, for £500,000 in 2021.
But Mr. Davies-Carr said he wanted to keep the boys "very grounded" in how they live their lives.
Charlie agrees with this view and says he doesn't use the "don't you know who I am?" card.
"It's not like I use it as an icebreaker or anything," he says.
"I was never going to use this as a fun fact."
Charlie says he doesn't want to come across as a show-off, so when asked about himself, he shares "something else a bit more boring."
"But my friends like to tell people sometimes, so it's hard to keep it a secret," he says.
"It slips out every now and then.
"And people are like, 'Oh, that's cool,' for about five minutes. Or they say, 'I don't know what that is.'"
A Long History
YouTube was founded on February 14, 2005, by three friends—Steve Chen, Chad Hurley, and Jawed Karim—all former employees of the online payment system PayPal.
While the first video published on April 23, 2005, wasn't quite Baby Shark, it did have an animal theme.
It was a 19-second clip called "Me at the zoo," posted by co-founder Jawed.
The founders opened the first YouTube headquarters in an office above a California pizza restaurant.
It is now owned by Google and has offices all over the world.
In the UK, 82% of adult internet users report using the platform—more than WhatsApp (80%), Facebook (76%), and Instagram (57%).