The app led one person to a friendly dog in the desert and another to a field of wildflowers. One young woman, after making her college decision, followed the app to a field where her school’s initials had been mowed into the grass.

And then there were the friends who followed the app to a suitcase full of human remains.

That is the gamble one takes with Randonautica, which claims to channel users’ “intentions” to produce nearby coordinates for exploration. Think: The law of attraction meets geocaching.

Randonautica makes a few asks of users — “What would you like to get?” “Choose your entropy source” — before prompting them to “focus on your intent” while it fetches coordinates. This process relies on location settings and a random number generator, which, despite what the company says, cannot be directly affected by human thoughts.

Many of the places users have been sent to since Randonautica became available in February are unremarkable: parking lots, grasslands, many bodies of water. However, interest has been driven by the spooky and often synchronistic “randonauting” stories many have shared on social media. While several of them appear to be fake, others have raised some cause for concern.

The creators of Randonautica say the app has evolved beyond their intentions. But what were those intentions?

A Brief History of Randonauting

Before Randonautica, there were the Randonauts: Strangers who swapped stories about their bot-assisted adventures into the unknown. They wanted to open their minds to the world around them and make meaning of life’s coincidences.

The bot’s code came from a group of programmers called the Fatum Project who were interested in, among other things, using the technology to ensure the randomness of online gambling outcomes.

Joshua Lengfelder, 29, discovered the Fatum Project on the messenger app Telegram in January 2019, in a fringe-science chat room. He absorbed the project’s theories about how random exploration could break people out of their predetermined realities, and how people could influence random outcomes with their minds.

Mr. Lengfelder, a former circus performer, thought the code and its underlying ideas could be used to explore the relationship between consciousness and technology. In February 2019, while caring for his father, who had just suffered a stroke, he created a Telegram bot that used the Fatum Project’s code to generate random coordinates. In March, he created a Randonauts subreddit, which now has 125,000 members. And in October, a developer named Simon Nishi McCorkindale created a web page for the bot.

That same month, Auburn Salcedo, the chief executive of Presley Media, an agency that creates brand integrations for TV, found the Randonauts on Reddit and offered to help Mr. Lengfelder get the word out. On Jan. 24, Ms. Salcedo and Mr. Lengfelder incorporated Randonauts, L.L.C., with her as C.O.O. and him as C.E.O. (She remains the chief executive of Presley Media, which handles P.R. for Randonautica.) They released a beta version of the app on Feb. 22.

Since its release, Randonautica has been downloaded 10.8 million times from the App Store and Google Play, according to the research firm Sensor Tower. After a few months of rapid growth, much of it propelled by TikTok, its downloads have started to taper off, according to data from the analytics firm App Annie.

In an interview in July, Mr. Lengfelder described Randonautica as “a multimedia storytelling platform” that encourages “performance art.” He said the overwhelming response has not surprised him.

“I kind of figured it was inevitable,” he said. “Because basically what it is is like a machine that creates memes and legends, and it kind of virally propagates on its own.”

On social media, the most popular randonauting videos feature eerie and seemingly dangerous situations that are dramatized through editing. Some creators have capitalized on the trend by posting exaggerated or false accounts of their randonauting adventures. The 27-year-old YouTuber Josh Yozura, for instance, claimed to have been led to a crime scene. (Mr. Yozura did not respond to multiple requests for comment.)

Ms. Salcedo denounced such videos in an interview with the YouTube creator Billschannel. In a phone interview this month, she spoke further about the proliferation of fake videos. “It’s so hard to manage, because people are really taking creative liberties after seeing how much traction the app is getting in that fear factor,” she said.

So How Does It Work?

On first use, Randonautica offers a brief intro and some tips (“Always Randonaut with a charged phone,” “Never trespass”) before prompting you to share your location.

Then it will ask you to choose which type of point you would like it to generate (the differences between which only matter if you believe the app can read your thoughts) before fetching coordinates from a random number generator. The user can then open that location in Google Maps to begin their journey.

Randonautica throws big words like “quantum” and “entropy” around a lot. Its creators believe that quantum random numbers are more likely to be influenced by human consciousness than non-quantum random numbers. This hypothesis is part of a theory Mr. Lengfelder refers to as “mind-machine interaction,” or M.M.I.: It posits that when you focus on your intent, you are influencing the numbers.

“Basically if you’re looking for any kind of peer-reviewed, scientific consensus, that does not exist yet in the literature,” Mr. Lengfelder said in a TikTok video in June, speaking about the theory. Instead, he pointed to the work of Dean Radin, a prominent figure in the pseudoscientific field of parapsychology, and the Princeton Engineering Anomalies Research (PEAR) program, which has cited Dr. Radin’s research, as evidence.

Randonautica claims that a 1998 PEAR experiment supported the idea that people can control random number generation with their thoughts. That study was published in the Journal of Scientific Exploration, which includes work about the paranormal, spirit possessions, poltergeists and questions about Shakespeare’s authorship. In the study, PEAR’s researchers wrote that the experiment was far from conclusive.

“It looks like they saw some kind of correlation, but they admit that it was weak and it needed to have further research associated with it,” said Casey Schwarz, an experimental physicist and assistant professor at Ursinus College who reviewed Randonautica’s claims for this article. She said she did not know of any quantum system that could be influenced by human thoughts.

Lisa Fazio, an assistant professor of psychology at Vanderbilt University, said that the more synchronous experiences were likely coincidences colored by confirmation bias, or the tendency to look for information that affirms one’s beliefs and tune out contradictory evidence.

She pointed to a story shared on Reddit, in which an Australian poster described being led to a map of the London underground. “Things like that happen all the time, it’s just that you don’t notice that map of London if you didn’t have the intention already to be thinking of London,” Dr. Fazio said. She also noted that coincidences are far more common than people realize.

Mr. Lengfelder dismissed such criticisms, stating that the app was not created to prove a hypothesis. “I would say it’s not some kind of academic science work,” he said. “We’re more like inventors than academic scientists.”

An update coming in August will feature improved graphics and, Mr. Lengfelder said, a custom random number generator that would have a higher “rate of entropy.” “So technically our M.M.I. effects should be higher,” he said. Of course, as noted above, M.M.I. is a theory that is not supported by science.

Daniel J. Rogers, a physicist who has worked with quantum random number generators, called Randonautica’s M.M.I. theory “completely absurd.”

“There is no quantum physics here,” said Dr. Rogers, a founder of the Global Disinformation Index. “This is just people using big science words to sound magical. There is no actual science here.”

‘Do Not Go Randonauting’

Randonauting became popular partly because of reverse psychology; young people approach it with a sense of foreboding. “Do not go randonauting” has become a popular title for videos.

Several people who shared unsettling stories about the app say they have since sworn it off. Adrian Chavez, 21, was led to an ominous beach near his home in Orange County, Calif. A video of his journey, posted on TikTok in early June, has been viewed 4.5 million times.

“I deleted the app right after that and never used it again since,” Mr. Chavez said in an interview in July.

The 18-year-old TikTok user who posted the viral video about finding a suitcase of human remains on a Seattle beach, @UghHenry, wrote in the comments of his video: “The moment I got back home, I broke down. I still can’t sleep.”

In an interview with The Atlantic, Mr. Lengfelder was blasé about the story, which was covered by news outlets including KING 5 News, The Mercury News and The New York Post. “It’s not the best press, but I’m not really that upset about it, because it’s kind of cool,” he said. “I kind of wish it was me who found it.”

Some adults have expressed concerns about the app’s lack of safety precautions for children. Though Randonautica’s terms of use specify that anyone who is a minor must obtain parental consent to use the app, such consent is collected by email, making it easy for young users to bypass.

Know and Tell, a child protection education program with the Granite State Children’s Alliance in New Hampshire, has posted on Instagram telling parents to keep young people off the app, or at least supervise their use.

“It was very apparent that these were young teenagers that were going to undisclosed areas in the middle of the night,” said Jana El-Sayed, the outreach project manager for the Granite State Children’s Alliance. She described these circumstances as “a perpetrator’s dream.”

Concerns about human trafficking and personal data use are addressed in Randonautica’s F.A.Q., which specifies that all location data is anonymized and only made available to developers, and that starting locations are never saved by the app.

Pokémon Go, which uses augmented reality to encourage local exploration, has handled safety concerns by putting PokéStops and Gyms in notable, public locations, and encouraging users to remain vigilant.

Randonautica’s safety tips are similar: Avoid dangerous areas, do not trespass, try to explore during the day or with friends. Randonautica’s website repeatedly urges users to “use common sense.” The latest version of the app will feature multiple screens and pop-ups reminding users to use the app safely.

Randonautica’s executives say they don’t understand why people would use the app to seek out risk or harm.

“You wouldn’t go out on a walk and say, ‘Let me think about seeing death,’” Ms. Salcedo said in an interview, referring to a viral TikTok video in which an 18-year-old user claims she set her intention as “death” and then happened upon a shooting victim.

“Yeah, ‘Let’s see if I get stalked,’” Mr. Lengfelder added.

Ms. Salcedo said Randonautica’s legal counsel reassured her and Mr. Lengfelder that the app would not be liable for any user misconduct.

“Is Google Maps liable too, for giving them directions?” Mr. Lengfelder said. “At a certain point, if somebody wants to really go out of the way and harm themselves, they’re going to do it. Whether it’s with Randonautica or not.”

Ben Decker contributed reporting.