At Cherry Blossom PUB, half the bar evokes nostalgia for Super Mario Bros. video games. The other half is full of cherry blossoms. (Kate Patterson for The Washington Post )

When Cherry Blossom PUB, the city’s most-talked-about pop-up bar, reached its final days recently, you could find more than 70 people quietly queued up outside at any given time, staring at their phones, whiling away the hours till it was their turn through the doors and into the sensory overload.

With its barbacks dressed as characters from “Super Mario Bros.,” cat-shaped ceramic tiki mugs and branches drooping with the weight of polyester pink blossoms hanging overhead, the Cherry Blossom PUB (for Pop Up Bar) in Shaw was the Kusama exhibit of the bar world, the answer to millennials’ obsession with novel experiences, perfect for selfies and also fleeting.

“From the moment you open, you’re three-deep till last call. You’ll see 800 to 1,200 people a night,” says Derek Brown, co-owner of the string of adjacent watering holes on Seventh Street that were transformed from quiet date spots to this buzzed-about tourist attraction.

Opened in March, it was gone by April.

But the insatiable craze for Instagram-worthy pop-up bars? Looks like it’s sticking around.

The notion of a pop-up is at least a decade old. Temporarily taking up residence in existing restaurants or bars, pop-ups have been frugal ways to test dishes and an aesthetic before signing a high-dollar lease and risking a reputation. Some drum up interest and investors. Some simply provide a creative outlet for someone with a day job and a dream.

But if you pay close attention to Washington’s dining scene, you’ll notice that there’s something different about the latest flurry of short-term supper clubs and bars.

At Radiator, the bar in the Mason & Rook hotel off the 14th Street corridor, bartenders are playing out a Sex on the Beach-fueled scene from the Tom Cruise classic “Cocktail” on the hotel rooftop. On H Street, a Will Ferrell-themed bar dubbed Stay Classy will take over the restaurant known as Mythology next month, staying as long as the crowds keep coming.

On Capitol Hill, the three-year-old restaurant Barrel last fall quietly turned its basement bar into a Trump-themed watering hole, replete with cardboard cutouts of the then-candidate and a menu of drinks that required customers to shout out some of the Donald’s most eyebrow-raising quotes. One bourbon-based quaff was called “How Stupid Are the People of Iowa?”

One factor driving this new wave of pop-ups: Washington is a city with so many restaurant and bar openings that few can keep track. Last summer, according to an informal count by the blog Eater, more than 80 restaurants opened in town. Taking closings into account, the Restaurant Association of Metropolitan Washington data showed that the city was up by a hundred restaurants and bars last year alone.

In this newly restaurant-saturated city, pop-ups have taken on the air of shake-ups. Radically new concepts every few months have become a way to seem like a new bar all over again.

“The exploding bar or restaurant scene, it’s nerve-racking in that you always have to attempt to stay relevant,” says Brad Ingwell, co-owner of Barrel.

Brown and his partners see at least a few more opportunities to exploit the craze. Another over-the-top pop-up bar is in the works; and the company has even hired its own special projects coordinator, whose skills include making authentic-looking tree branches and getting the lights to blink on cue. As for the sherry bar, whiskey bar and oyster bar that the new pop-up could occupy? Brown speaks about them in the past tense.

“Sometimes you get blindsided by your own interests and the things that you like, and you realize there’s a variety of interests that people have going into a bar, and a variety of things that they want to see,” says Brown. “Not everybody is coming just for the drinks. ”

People lined up for hours to get into the blossom bar, which was open for a little more than a month. (Kate Patterson/for The Washington Post)

Even the drinks bore out the theme: One rum agricole tiki-style drink came in its own ceramic lucky cat. (Kate Patterson/for The Washington Post)

Brown first opened Miracle on Seventh, a temporary all-things-Christmas bar for one month in 2015, masking the walls of Mockingbird Hill, the sherry-focused bar, behind hundreds of yards of wrapping paper. The waits to get inside grew to an hour or more. And so the bar returned this past Christmas.

The success of the Trump Bar — it also drew a line, and media coverage — prodded the staff to turn Barrel’s bar into a kind of running joke, transforming it into a “Seinfeld”-themed bar for the holidays, an elaborately decorated Russian-slash-authoritarian bar to coincide with the inauguration (nearly every cocktail featured vodka), and an over-the-top Irish bar called the Smashed Potato for St. Patrick’s Day (sample beverage offering: “Addicted to Craic”). It will return as a Kentucky Derby bar when the ponies race next month.

Barrel’s revolving pop-ups, says Parker Girard, the bar’s beverage director, are “as much about keeping the old people as it is about attracting the new.

“It’s really hard to remain cool. Coolness is something you can never put your finger on.”

Girard’s inspiration weren’t other pop-ups but bars such as Trick Dog in San Francisco and Pouring Ribbons in New York, which upend their themes and cocktail lists regularly to keep things fresh. A certain theatrical variability has invaded the dining and drinking scene elsewhere, too: In Chicago, chef Grant Achatz’s Next turns from steakhouse into a Chinese restaurant, to, um, the defunct El Bulli as regularly as some of us go out to a fancy dinner. Beetle House, a pop-up bar whose theme is — wait for it — the director Tim Burton, has been drawing crowds in New York and will soon expand to Los Angeles.

At Barrel, “What it allows us to do is play with ideas that definitely couldn’t work as a whole bar,” says Girard.

Brown agrees that the chance to flex creative muscles is part of the allure.

“If you’re in this business as a creative outlet, it gets boring to sling the same thing over and over again,” he says.

But beyond the next pop-up or two, Brown won’t commit to saying that the business model is here to stay.

“There will be a time, I think, that it jumps the shark, that people will tire of seeing novel bars,” he says with a laugh. “I don’t know when that will be, but we’ll see it, if we last that long — because nobody will show up at our bars anymore.”