Are you playing ‘Pokémon Go?’

A young couple hurries through Cambridge Common near Harvard Square, a bit frazzled, pausing to ask a group of strangers, “Do you know where the Squirtle went?”

A pair of 20-something guys wanders through Boston Common, noses buried in cellphones. “Over here,” one says, and they hustle off.

And in Davis Square’s Kenney Park, a small army holds court on a Saturday night, waiting to see what it might find, never mind the hour (midnight) or the weather (rainy).

This is life in the world of “Pokémon Go,” the recently released, ridiculously popular smartphone game that has turned the streets of Boston — and every other American city, for that matter — into a fertile Pokémon hunting ground.

The free app debuted last week, immediately becoming one of the country’s most downloaded and sending Nintendo stock soaring. The game could be most aptly described as a scavenger hunt, though users aren’t searching for actual objects. Using augmented reality and GPS technology, the game sends users off in search of virtual images found in real-world locations.

If a player is in just the right place, images of Horseas or Kinglers or other odd creatures automatically — some might say magically — appear on their cellphone screens, allowing users to “capture” them. The chase has sent legions of players out to local streets, parks, and neighborhoods in search of creatures and hot spots.

Take Elizabeth Billings, for example, a Tufts student who spent Sunday afternoon at Kenney Park, a popular gathering spot for players. The day before, she and friends played for seven straight hours, walking 11 miles in the process (like a Fitbit, the game tracks the distance its users travel).

“Our schedule the past two days has been shaped around ‘Pokémon Go,’ basically,” said the 21-year-old biomedical engineering major. “We caught a Bellsprout at the grocery store.”

Then there was Kortni Violette, 25, who reported a Saturday Pokémon expedition that, by the time she looked up from her screen, had gotten a little out of hand.

“I had walked, like, three miles from home without knowing,” she said. “I had to call [my boyfriend] to come pick me up.”

Her experience was not unusual — so much so that Woburn Police Chief Robert J. Ferullo Jr. felt compelled to send a tweet Sunday urging residents to “please make good decisions if you are playing ‘Pokémon Go,’ stay aware of your surroundings.”

Created by Google spinoff Niantic Inc., “Pokémon Go” is a carry-over from previous Pokémon games, which involve a world full of oddly-shaped “pocket monsters” that are to be captured, tamed, and sent into battle against each other. The original Pokémon game debuted in 1996, and in the years since has grown into a powerful brand that includes movies, television series, and an array of merchandise.

While the new game’s primary audience appears to be millennials, many of whom grew up playing older iterations of Pokémon games, a litany of others are taking part: children, even the occasional baby boomer.

From left, Mary Baker, 18, Rupert Simpson, 20, Isabella Marini, 19, and Andrew Bissel, 19, played “Pokémon Go” on their smartphones Monday.Keith Bedford/Globe Staff/Globe Staff

Tom Gould, 55, became aware of the game when his 10-year-old son, Adam, downloaded it onto his phone late last week. But in the time since, Gould has found himself firing up the app.

On Sunday, standing in Davis Square, he proudly relayed a story about a recent gas-station stop that resulted in something of a Pokémon coup.

“I was filling up and I had a minute of downtime and I caught . . . ”

He turned to his son.

“Adam, what’s the little bird creature?”

“Spearow,” said the boy, not looking up from his own game.

Given the game’s popularity, it’s no surprise that it has wrought countless headlines, a few of them quite strange.

In Wyoming, for example, a woman happened upon a dead body as she was playing the game along the Wind River. A Reddit commenter, who found himself playing the game at 3 a.m. at a park with two strangers, said he had to convince a passing police officer that the group wasn’t doing anything illegal.

The game places characters in scenes viewed through smartphone cameras, such as Kenney Park, Somerville.Alex Crease

And in Holyoke, 45-year-old Boon Sheridan was surprised to learn over the weekend that his house, a former church, had been deemed by the game to be a “gym” — something that, like a “lure,” attracts countless “Pokémon Go” players.

On Saturday, he watched from his couch as a steady convoy of cars pulled up, idling outside.

“My poor neighbors probably think, ‘Oh, we live next door to a drug dealer, [with] people showing up at all hours,’ ” Sheridan said. “Luckily, no one gets out and runs up to the house.”

There have been various reports, meanwhile, of bruises and twisted ankles as distracted hunters have walked into walls or stepped off curbs. And there was at least one reported case, in Missouri, of someone using “Pokémon Go” to set up an armed robbery.

Undeterred by the potential dangers, however, a trio of Pokémon hunters — Alex Crease, 21, Madeline Gorchels, 22, and Claire Diehl, 22 — set off together on a Sunday afternoon Pokémon trek, one that would ultimately last six hours and cover 6 miles.

Making their way down Massachusetts Avenue in Cambridge, they kept close tabs on their phones, stopping occasionally to capture small, cartoonish creatures that appeared on the screen.

Everywhere the trio went, it seemed, they found others doing the same thing.

As with any wildly popular game, it’s difficult to predict how long this Pokémon craze might last; whether the game has the staying power of, say, “Angry Birds,” will become apparent only with time. It wouldn’t be unheard of, in today’s ever-changing tech environment, for another addictive game to sprout up soon.

Already, players have reported issues with the game, from its penchant for quickly sapping phone batteries to log-in issues stemming from the game’s widespread use. The Guardian raised security concerns, saying users may be unknowingly handing over their e-mails, search history, and Google drive data.

For now, though, fans seem happy to devote chunks of free time to chasing cartoon birds and sea horses.

By 6 p.m., having trekked from Davis Square all the way to the Charles River near Harvard University, Crease, Gorchels, and Diehl walked along the water chatting causally. It was cool and overcast, nightfall not too far off. There had been talk about getting dinner, maybe turning back toward Somerville. Already, they had been out for more than two hours.

As they approached a nearby bridge, however, Crease — his phone inches from his face — said, “Oh, wait — there’s a ‘lure’ over here!”

And with that, the three friends forged ahead, eager to see what awaited them.