Recently, I bought a T-shirt from Rob Sheridan, the co-founder of the design company Glitch Goods and the former art director for the industrial rock band Nine Inch Nails. It’s a sleeveless black muscle shirt that has an eyeless melting Barbie doll face dripping with blood and set against a fiery backdrop and says, ominously, “This Barbie opened the ark of the covenant … She betrayed the word of God.” Mr. Sheridan promoted the shirt to coincide with the same-day opening of Greta Gerwig’s “Barbie” and Christopher Nolan’s “Oppenheimer,” a new, unofficial phenomenon the moviegoing masses have called “Barbenheimer.”

I regret to inform anyone who has ever had any kind of respect for me that I have been brainwashed by the internet into not just participating in this organic marketing event but also thoroughly enjoying it. I plan to see both movies on the same day, probably while wearing a Barbie melty-face T-shirt. At least 40,000 other moviegoers are apparently doing the same thing and have already purchased tickets.

This is the kind of thing that can happen only because the internet exists, and that’s part of the fun of it. It’s an absurd juxtaposition: Mr. Nolan’s dark history of a man-made existential threat and Ms. Gerwig’s gleefully ironic interpretation of Barbie’s upbeat pink bubble. If the films have anything in common, it’s that they both explore a macro view of humanity, one through the lens of state power and personal morality, and the other through patriarchy and consumer culture.

Absurd juxtapositions are, of course, the bedrock of comedy, and the “Oppenheimer”-“Barbie” pairing has resulted in a fount of hilarity, including memes, homemade goods and celebratory events designed by fans who plan to extract the maximum amount of entertainment from both.

It’s easy for this kind of activity to develop online because the tools for creativity are so available, they’re practically free. You can watch the idea generation happen in real time on social platforms, see fan communities bond over it and participate yourself, if you’re so inclined.

The memes in particular — lots of glittery pink mushroom clouds and dark scary Barbies — are their own genre of creative work; the fact that they double as marketing for the films is an inevitable but unintended side effect. Barbenheimer memes are both an organic expression of fan enthusiasm and a critique of modern consumerism. One of my favorites is a video shot from the perspective of two people watching a plane skywrite “Barbie” via contrail in the signature Barbie font. Just as an offscreen voice comments in a reverent tone, “next level movie advertising,” a giant bubble gum pink mushroom cloud explodes on the horizon, and sirens wail.

Mr. Sheridan, who refers to himself on Twitter as “Meme Grandpa,” spent his childhood melting Barbies and G.I. Joes to make mutant creatures (a terrible cliché for a straight cisgender boy, he admits). The Barbenheimer meme “plays with the most extreme polarities of old-fashioned gender stereotypes (Barbie is for girls, World War II movies are for boys) and smashes them together,” he says. “And that’s a really fun playground for people now at a time when we’re finally deconstructing gender.”

Technically, my shirt’s ark of the covenant, melting-face imagery is a reference to “Raiders of the Lost Ark,” but “Now I am become death, destroyer of worlds,” the line J. Robert Oppenheimer claimed to have thought upon viewing the detonation of the first nuclear device, has a similar vibe. As is often the case with memes, it’s hard to tease out exactly where one reference ends and another begins, which feels appropriate: We live in a world where there is war and famine, but also Taylor Swift, and our tiny brains have to reconcile the horror with the sublime every day. Social media heightens that contrast by feeding people a steady stream of unrelated topics, sequenced by black box algorithms designed to appeal to both fear and joy, in the hopes that some particular sequence will eventually cause their wallets to open and money to float out.

On top of that, the consumer landscape is increasingly blanketed with arbitrary crossovers and product tie-ins, some of which are brilliant and some of which are questionable. The weirder the crossover, the more likely it goes viral. Did the world need Arizona Iced Tea-branded Adidas sneakers marketed for 99 cents? No. Did they attract so many potential buyers that the New York Police Department had to shut the sale down at the pop-up store selling them? Yes.

The “Barbie” marketing team absolutely understands this, and the absurd brand-collaboration drops have spread with the speed of the 1854 cholera outbreak in London. There’s a real-world Barbie dream house on Airbnb, Barbie Krispy Kreme doughnuts, Barbie rugs and a Barbie Xbox. Surprisingly, there is no Barbie Pepto Bismol, which seems like a natural fit in terms of existing I.P. and what brands now refer to as colorways.

The “Oppenheimer” team’s marketing efforts have, unsurprisingly, been a little less aggressive, and there have been no official crossovers because nuclear bombs are not what advertisers refer to as “brand safe.” A “Barbie”-“Oppenheimer” edition of Pop Rocks, however delicious, would be distasteful.

I would have bought them, though, because, despite my Gen X-y disdain for the Man trying to sell me things, this kind of marketing is basically a form of entertainment, and I like clever, ironic things way more than I should, and the fact that so much of it is generated by fans launders some of the commercial ickiness.

Here I should note that my personal vibe is more “Oppenheimer” than “Barbie,” by some order of magnitude. I did own Barbies when I was a kid, but I played with them so infrequently that they remained fairly pristine (unlike the ones my friends owned, which tended to end up scribbled on, decapitated and chewed on by pets). I just had no desire to cosplay traditional femininity, even as a kid in a conservative household. Mattel’s efforts to create Barbies with jobs and other interests came too late for me, and, in any case, didn’t match my early work trajectory. (Walmart cashier Barbie, where are you?) I was way more into my chemistry set; after I ran out of sanctioned experiments, I just threw together chemicals and hoped for an explosion.

Maybe because of this, I am a little embarrassed by how taken in I am with the “Barbie” piece of Barbenheimer. I’m still a little resentful of having been told I should be interested in dolls and pink things. (My wardrobe skews black, which matches my heart.) I could pretend it’s just my admiration for Greta Gerwig and Margot Robbie that makes me so excited to see the movie, but the truth is, I want to see it because it looks, well, fun? And a Barbenheimer double feature? At first glance, it seems like they don’t go together, but you could say the same thing about chicken and waffles, and they are delicious, so count me in. I am intentionally letting myself be indoctrinated into total Barbenheimer madness. That might make me a sucker according to my generation’s unwritten rules about the degree to which it’s acceptable to be co-opted by brands, but this moment isn’t just corporate manipulation. It’s a product of fan culture, the internet and a fortuitous timing coincidence. I am completely into it.

Elizabeth Spiers, a contributing Opinion writer, is a journalist and digital media strategist.

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