Marc Sebastian, like many people, first started seeing the cruise videos around the holidays.

After Royal Caribbean's "Ultimate World Cruise" set sail from Miami in mid-December, many passengers started filming their daily routines at sea, from hanging wet laundry in their cabinet-sized bathrooms to piling their plates high at the dining room buffet.

They posted highlight reels of their excursions at ports throughout the Caribbean and South America, the first of hundreds of stops on their nine-month journey around all seven continents. Their videos flooded TikTok almost immediately, captivating viewers at home.

Onlookers wondered about the practicalities of life on board the cruise, which was first announced in late 2021 and starts around $59,999. And they relished the potential for drama, especially since aspiring passengers can theoretically join at any time for individual "segments" before the cruise docks in September.

Many posted that they wished reality TV cameras would come on board to document it all. Sebastian, a 33-year-old content creator based in Los Angeles, was one of them.

"Put cameras on that ship right now ... There's gonna be mutiny. There's gonna be blood. Someone is going overboard, I want to watch," Sebastian said in a December TikTok that's since gotten more than 1.3 million likes. "Bravo, where are you?"

In the absence of camera crews, viewers have turned to TikTokkers to follow along for the journey.

They include the accounts of more than two dozen fast-emerging "cruise influencers" on board, as well as a growing handful of content creators across the U.S. and U.K. who are cross-referencing, synthesizing and analyzing their videos in posts of their own.

They've been answering questions and updating viewers on the cruise's latest new "characters" and storylines, from minor flooding to a rumored wine shortage.

By the start of the 2024, the hashtag #UltimateWorldCruise had surpassed 150 million views and become its own form of must-see TV, all on TikTok.

"It's been fun to kind of just follow what truly feels like a TikTok reality show," said Kara Harms, the founder of a lifestyle travel website who has been posting videos and a now-viral bingo card about the cruise from her home in San Francisco.

"The way that we're getting higher-produced content from some people and then some more raw, gossipy content from other people really does feel like you could stitch everything together and make an episode for every single day," she added.

Nine months on a cruise ship is just the kind of "social incubator" that's so central to reality TV, said Jamie Cohen, a media studies professor at Queens College who began his career as a reality television producer.

But he says there are some key differences. Whereas TV producers typically hold the keys to casting and plot points, it's the viewers who are shaping the #CruiseTok narrative, by reacting to and interacting with the passengers' posts in real time.

Social media users are effectively "opening the door to plot lines that create reality around the people who are just on the ship to enjoy themselves," Cohen added. The risk is that people at home or on board might change their behavior or even manufacture drama for views.

That's something most of the nine-month cruisers are acutely aware of and trying to avoid, several passengers told NPR. Not Sebastian, though.

"Alternately, put me on the cruise," he said in his December video. "I will cause chaos, I will wreak havoc, and I will record everything."

Within days, he was on board.

Discovering the truth behind the reality show

Atria Books, a division of Simon & Schuster, paid for Sebastian to join the cruise for 18 nights, on a stretch that included the Drake Passage and Antarctica.

His duties included promoting their books through a virtual book club, in which thousands of humans and a handful of penguins participated. He's since passed the torch to another cruiser.

Sebastian told NPR towards the end of his time on board that while he arrived ready to play the part of a villain — including packing an "evil"-looking long red coat — he wasn't serious about causing drama.

"I really did think at the very beginning that I was going to find a lot of interpersonal drama within the people," he said. "But unfortunately, they're all so nice — crazy! — and they are all really kind. There's a really amazing sense of community."

Sebastian documented everything, posting candid reviews of the food, accommodations and other aspects of the cruise on a scale of "fabulous," to "pressing charges" to "prison, honey." He made clear throughout the trip that he was not a fan of cruises to begin with, and had criticisms of this one.

His trip wasn't devoid of drama. Some memorable moments included him getting scolded for profanity, forming alliances for (boat) tenders, getting kicked out of a members-only lounge and the reservation incident.

But Sebastian says nearly all of the conflict came from members of the cruise community online, whom he says tended to be older and mistake his bluntness for ungratefulness.

"I do feel really lucky," he added. "But I don't feel lucky that I'm on a cruise. I feel lucky that a brand noticed that I made content and trusted me enough to put me forth into this experience."

Royal Caribbean did not respond to multiple requests for comment.

Jenny Honeycutt (aka @drjennytravels), a 34-year-old writing consultant and full-time traveler, spent time with Sebastian on board. She says he was "extremely respectful" about not filming or posting videos of people without their consent, a practice she recommends for any future influencers who may join the ship.

She says the way the outside world is portraying passengers as reality show characters, while amusing, has stirred up some negativity on board.

"Everyone has paid a lot of money and given up a lot in some way or another to be here, whether it be their families, their homes, their pets," added Honeycutt. "So I think people have a fear of this taking away from this adventure that it is."

The "cruise influencers" have also gained a lot, chiefly, hundreds of thousands of social media followers each. But most of them couldn't have predicted they would go viral overnight — let alone have to add "film and post daily TikToks" to their vacation to-do lists.

Not all passengers set out to become influencers

The so-called cast of characters documenting their cruise travels on TikTok is large and growing.

There are Gen Z-ers and retirees, solo travelers and entire families, crew members and performers, duos of spouses and of siblings.

Passengers chose the cruise for a variety of reasons, from celebrating a retirement to spending an inheritance or simply wanting to see the world.

Some, like Amike Oosthuizen, boarded the ship with a sizable social media following already.

The 26-year-old had done some influencing back home in South Africa (her mom, incidentally, is one of the stars of Real Housewives of Pretoria). Oosthuizen says she joined the trip with plans to post "day in the life" videos, with a focus on makeup and fashion.

"I really did it because I wanted to capture the memories and there's so many places we were seeing," Oosthuizen said. "And it was such a bonus that it actually blew up and everyone wanted to see what we're doing. So now it's more like I want to keep everyone updated."

She says she spends two to three hours a day editing her footage into videos, and has already been approached by brands for potential partnerships. Most of these companies are offering excursions at upcoming ports, since she can't receive packages on the ship.

Oosthuizen, who is working remotely as a regulatory officer for an agriculture company, says she hopes those opportunities — and the chance to be a full-time influencer — will continue even past the cruise.

Joe Martucci, on the other hand, never wanted to become TikTok famous. The 67-year-old, who is traveling with his wife to celebrate his recent retirement from the finance industry, wasn't on the platform at all.

He started making daily videos to send to their four adult children, who live all over the world. They encouraged him to start posting them on TikTok, which Martucci suspects has something to do with his tendency to mispronounce words. He set up an account called @spendingourkidsinheritance, which he emphasizes is a joke.

"Then I had to figure out how to post something to Tik Tok," he said. "And two of my daughters said, let's put these — I thought they said hash marks, but they're hashtags."

His first video took off, garnering more than 400,000 views, and he's continued posting daily recaps ever since. Each video still opens with a cheery "hey, kids" — only now he's addressing not just his own children, but the 90,000 or so "adopted kids" who now follow him.

"Some people have said, 'We hear more from you than we hear from our own parents," Martucci said, recounting the touching messages he's received since. "We're overwhelmed, we're very humbled and we like the fact that people like watching what we're doing."

The couple doesn't plan to start monetizing their videos, or stop posting them, anytime soon.

But they had a close call this week. On Wednesday, Martucci tearfully announced on the platform that their account had been hacked, saying the culprit had asked his contacts for money.

He told NPR later that same day that some five other TikTokers on board the cruise had rushed to their room to help them change their password and set up two-factor authentication. The passengers had learned about the hack from a TikTok posted by one of the cruise commentators on shore.

Other viewers on land, he said, were using their TikTok connections to try to help them get their old username back.

Passengers say the drama isn't coming from the ship

Viewers on land can't seem to get enough cruise content.

About half of the items on Harms' viral bingo card — which Sebastian cheekily played on board — have already been crossed off, including fist fight, COVID outbreak, petty neighbor drama, cliques forming, an early departure and a (sort of) pirate takeover.

Kisha Peart, one of the at-home cruise commentators, told NPR that she originally started posting to share her insights as a former cruise ship employee. But the actress and waitress says she now spends hours a day researching, recording and editing TikToks — and doesn't plan to stop anytime soon.

"It is kind of a lot taking it all in but it's also been fun," she said. "So it's been exciting being like, 'Okay, what happened today?' And I'll deep dive and try to bring the info to the people."

She's one of many TikTokkers reporting on the latest cruise ship "tea." At least, that's what they're calling it. Harms, of bingo card fame, says viewers are so excited about the potential for drama that they may be misusing the word.

"When you peel back the layers and look at it objectively you're like, that's just humans being humans," Harms said. "It's not actually drama and tea."

Several nine-month cruisers told NPR that they feel the drama is coming not from the passengers, but from people watching at home.

Without naming names, Honeycutt said some recap accounts are doing a great job while others are stirring the pot.

"There's kind of been this pall even on the ship of, what are we as the TikTokkers posting versus what's going on?" she added.

She said the TikTokers on board have gotten together several times — including once at a private dining experience at Royal Caribbean's invitation — to make videos, bond about their love of travel and sometimes vent about the negative comments.

More than 30 cruise influencers are now in a group chat, Oosthuizen said. She said they see each other pretty often, in passing and on purpose — but not always to make content.

"Sometimes it's just nice being with the other creators and just chatting and catching up and not pulling your phone out and recording everything," she said. "We get together a lot more than we actually record."

Martucci described the cruise as "a floating city of 2,000 people," and said he didn't feel anyone was intentionally trying to cause drama on board. In fact, he said Wednesday, the response to his account being hacked demonstrated how "we all look after each other."

"We all respect that people who are on this ship spent a lot of money to be on this ship," he said. "And this is their vacation. This is their life story. And they need to be able to enjoy their life's dream."

Peart, at home in New York City, acknowledged that she has played a role in hyping up the reality TV aspect of the cruise, by putting people in the spotlight and adding "a little pizzazz onto what's already out there." But she says it's not malicious, and all in good fun.

"At the end of the day, we're all on TikTok to be entertained," she added.

The cruise hype reflects the state of social media, and could hint at its future

We're not likely to stop hearing about the nine-month cruise anytime soon.

More travelers will likely come on board, including more influencers. Australian comedian Christian Hull, who has been posting excitedly for weeks, will be joining the ship when it docks in Brisbane in March.

He told LiSTNR's "The Briefing Podcast" that he took $20,000 out of his mortgage to pay for a balcony room for 16 days.

"I got sucked right in," he said, adding that he hopes a sponsor will eventually cover the cost.

Several influencers told NPR they think Sebastian's novel partnership with Atria Books could help usher in a change with how brand partnerships work.

Harms, for example, thinks people should expect more "integrated" campaigns in the near future, where products are advertised more organically on social media. That could mean, for example, an influencer showing their journey on a walk to advertise a pair of sneakers, rather than talking into the camera about them.

Sebastian said he'd be thrilled to see more brands using trips and experiences to market goods. He'd also like to see influencers being more honest about the things they're promoting, as he was about his time on board.

"I hope that this takes off and allows other people to see you don't need to have this toxic positivity when it comes to influencing, and that you can express how you actually feel about something," he added.

At the same time, the cruise hype also illustrates the potential risks of virality and social media culture itself. Hacking is just one example.

"The majority of these humans that are on here aren't previously known influencers. They're becoming that," said Cohen, the former reality TV producer. "So it is one of those things where creating drama ... could create adverse results."

Cohen views this as an experiment that can hopefully offer insights into better policy for future cruises when it comes to things like privacy and cameras on board.

He acknowledges that cameras and vlogs are ubiquitous today, at least among Gen Z. And he hopes those who may be tempted to cause a scene for views or stir the pot in the comments section will remember that "these are all humans; we could be the other person."

Cohen says social media audiences have a lot more power than they realize to "bend and mold the way that these things go," and urges them to use it responsibly.

"I think it's important to enjoy them," he says of the TikToks. "I don't think there's a reason to try to change reality."