Have you seen the viral video where a choir of gummy bears sing a rousing chorus of Adele's Someone Like You?
Or maybe the slightly bizarre sight of people putting make-up on potatoes?
Or perhaps you have been out and about and someone has inexplicably shouted "hit or miss" at you?
These seemingly unconnected experiences all share one thing in common - they are memes on TikTok, the short-form video app that you may not have heard of if you are over the age of 35.
For those who use it, it is a big deal and the app is looking to extend its reach to new demographics all the time.
Owned by Chinese internet firm Bytedance, the app was first launched in China in 2016 with the name Douyin and grew to 100 million users in the space of a single year, with a billion views daily.
It went on to become the most downloaded app in China and Thailand by the start of 2018, and in October was the third most downloaded app globally.
And it has not done badly in the West either, with 80 million downloads in the US.
In 2017, Bytedance purchased Musical.ly - another short video music app with which parents of young children may be familiar - increasing awareness and adding 30 million more users.
It now has more than half a billion active users, with 40% of those outside China.
Videos created on TikTok are generally no longer than 15 seconds - although it has experimented recently with longer clips and some star users are allowed to make videos of up to 59 seconds. Adverts have also recently been spotted on the site as it looks for ways to monetise its content.
All the clips are based around themes, such as music, cooking, dance or fashion.
Previously, Bytedance had focused on news, with an app called Toutiao which used AI algorithms to learn user preferences. The same AI is used to provide relevant videos to TikTok users.
TikTok has a bunch of clever movie studio-style special effects, such as an editing tool that allows people to appear to move objects with their minds.
"TikTok has tapped into a successful model of user-generated content by making professional-quality video creation simple and accessible," said Paul Barnes, managing director of analytics company App Annie.
And while it is not the first of its kind - remember Vine? - it has proved far more durable.
"Vine popularised the short-form video format, but it was much harder to create a quality video. You were really left to your own devices, and needed a high level of technical expertise, along with talent as a performer, to create something people wanted to watch," said Mr Barnes.
"In contrast, the editing features in TikTok and the relatively straightforward nature of lip-syncing means it's easier than ever before to create original video content."
TikTok is often applauded for being one of the few happy places on the internet - its silly video clips contrast starkly with some of the darker content on YouTube.
That may not last, thinks Charlotte McEleny, publisher of marketing magazine The Drum.
"No user-generated, or mostly user-governed platform, is ever going to be squeaky clean. What it can and should do is learn from those errors made before, as there is a tough balancing for these platforms to make in allowing creativity and self-expression, while also wanting to protect users from inappropriate content."
Who uses TikTok?
Sophie is 12 (so in theory not old enough to use the app which is officially for 13-year-olds and over) She, like many youngsters, came to it via Musical.ly, and has parental approval to use TikTok. She says she used it more when it was Musical.ly, but likes the ephemeral nature of its content.
"You can go on for one minute, the videos are 15 seconds long so you can watch a lot in a short time," she said.
Munavar Zeb is 32 and lives in the Indian city of Surat. He has been on TikTok for more than a year and likes to post videos of himself, which he makes on a Sunday, his only day off work.
"I think the basic fundamental thing which appeals is that one can act, dance, sing, and do whatever you are good at in front of a camera and upload the same to get liked by the world and ultimately become famous," he told the BBC
"I don't know about everyone but, yes I feel very excited and happy whenever my video is being liked by someone."
Laurie Elle is a 20-year-old from Manchester who has more than 2.5 million followers on TikTok, and has been invited to attend some of its offline events. As a dancer, she uses it primarily to share dance videos.
She says that she finds the app really easy to use. "You can film the videos straight from your phone and add effects in the app, you don't need any professional equipment to use TikTok.
"The trends on the app are also really popular, fun and easy to get involved in so it gives everyone a chance to share their own content and get creative," she said.
She told the BBC that, while the app is largely free of "negative content", it is the online space where she personally receives the "most negative comments and messages", although TikTok does have the option to disable these.
Love it or hate it, it could soon become hard to avoid, in part because whenever a meme or clip from the app appears on the web, the branding is watermarked on it with people invited to visit the site, a clever piece of marketing that is making its name stand out amid the ton of anonymous web content.
That, and the fact that it has concentrated on one thing - user-driven video - could mean Bytedance can achieve what bigger, rival platforms like Tencent and Baidu have not - breaking into the conscience of Western users too.
"It's interesting that something so single-minded has done that, over the hugely successful WeChat in China. A lot of people looked at WeChat and thought that would be the crossover app," said Ms McEleny.
"While most young Chinese will order, pay and socialise through it constantly, that behaviour hasn't translated as well into Europe and America."
TikTok was given a boast in terms of visibility in America, when US talk show host Jimmy Fallon promoted the app and initiated a campaign #TumbleweedChallenge.
In the challenge, people roll on the ground to music associated with Western movies.
Since November 2018, when Mr Fallon mentioned it on The Tonight Show, more than nine million videos have been tagged #TumbleweedChallenge on the app.
For TikTok, there seems to be no tumbleweed moment as it sweeps its way through more and more countries, picking up new users at every turn.