It started as a prank—a flippant yet innocent April Fool’s Day post on First Avenue’s Instagram: Tickets for a Trader Joe’s vs. Aldi dance party were going on sale later that month. “A massive immersive experience,” the post read. “Grocery store–inspired rave couture encouraged!”

First Ave general manager Nate Kranz remembers seeing the post. “I was like, Ha, marketing and social media team,” he says. “Nice one.”

And then he forgot about it and went along with his day—until he couldn’t. The post went viral, garnering nearly 12,000 likes—thousands more than posts about actual shows and raves, even more than a photo of Bruce Springsteen’s freshly painted star outside. “No but you see I would pay good money,” one comment read. “Finally, a place to do the shopping cart,” said another, ending with the dancing-guy emoji. Our own internal Mpls.St.Paul Teams chats were afire with similar messages: “I’d actually love that,” I confessed to digital editor Peter Diamond, a fellow grocery-aficionado millennial. I ignored his virtual laughter and started daydreaming about the minidress I could sew from Trader Joe’s canvas tote bags.

“And it wasn’t just local,” Kranz says. First Ave received emails, texts, and calls from fellow venue owners and managers across the country, all asking about the rave. “Some realized it was April Fool’s and some didn’t,” he says. “Some wanted to know who we booked as the DJ.”

In the world of Shrek raves, a grocery store–themed dance party didn’t seem too over the top. The wheels of Kranz’s marketing team started turning, and in just over a week, to the internet version of cheers and applause, an actual, certifiable Trader Joe’s vs. Aldi rave was announced for July 10.

But to fully understand how we got here, we need to back up a little. Probably all the way to the Shrek raves (yes, you read that correctly) and actually, maybe even a little further back, to the underlying reason why the concept of a rave celebrating the cult followings of two grocery stores really isn’t too over the top, especially for the mid-20s-through-late-30s demographic hitting up the various dance floors controlled by First Avenue Productions. Glance at First Ave’s big calendar any given month, and you’ll find raves and dance parties tied to nostalgic time periods or artists: There are the 2000s-era “recession pop” parties and the “Miss Jackson If You’re Nasty” Janet Jackson dance night on July 17 and even dance nights connected to pop culture touchstones like HBO’s closeted-hockey hit Heated Rivalry. And yes, there’s one for everyone’s favorite green Scottish ogre. All have proven to be the catnip for millennial ravers.

“The thing is, First Ave used to have dance nights all the time,” Kranz reminds me. “When I started in the ’90s, there were five dance nights a week. People of a certain vintage will remember that even on weekends, the concerts got done at 10, and we turned things around to these themed disco nights.”

Now, First Ave uses dance parties strategically to fill open slots on the calendar and get creative with its audiences, marketing them with a little bit of FOMO induction and scarcity mindset—attendees never really know when or if a theme will return. These hyper-niche themes really started taking off about four years ago, right around the time L.A.-based artist Jordan Craig, also known as Ka5sh, brought the first Shrek raves to L.A. and Brooklyn with massive success. Craig proved that attendees were more than willing to go along with the theme: They would wear green face paint and even style their hair into Lord Farquaad–esque micro-fringed bobs.

“When I first saw the Shrek rave on our calendar, I said, ‘What the hell is that?’” Kranz admits. “Imagine my surprise when we sold it out.” First Ave considers a sellout around 1,500 tickets; these dance nights often host upwards of 1,000. Sure, it might be a marketing gimmick, but it’s a marketing gimmick that works, people!

“When you lean into a niche that’s kind of weird and fun and quirky, it just brings out the best in people,” says DJ Hampster Dance (government name: Jeff Atchison), the local DJ mastermind behind many of these themed nights, including the upcoming Trader Joe’s vs. Aldi set. And he would know: “Weird and fun and quirky” is his raison d’être. In addition to DJing theme dance nights, Twins games, and other events, he built his massive social media following on his unexpected mash-ups (think “The Bare Necessities” from The Jungle Book crossed with Afroman’s “Crazy Rap,” or Wicked’s “Defying Gravity” with The Killers’ “Mr. Brightside”).

He got the gig essentially the same way the gig was born: right place, right time, right energy. When he hosted a 2010s night at First Ave on April 3, the team was already asking if he’d host what will clearly be the party of the century. He was, to no one’s surprise, immediately down for the admittedly nebulous grocery store rivalry concept.

“The thing is, Aldi doesn’t really play music, so I’m still trying to figure that out,” Atchison muses. “But the Trader Joe’s vibe—that’s ’80s and ’90s, indie alts, but also some electronic, some Daft Punk. Very fluid.”

He’s hoping that, in addition to raising a solid chunk of change for food shelves (part of ticket sales), attendees will go all out with costuming, like they do for other shows: the TJ’s-employee-chic Hawaiian shirts and red oval name tags; bespoke reusable bag couture (the kind I’ve been mentally envisioning for months!). He’s hoping people use the TJ’s vs. Aldi rave as a chance to be silly and weird, to have a little fun without taking any of it too seriously, to let inhibitions hit the (dairy aisle) floor. And the instigators at First Ave hope the same thing: for whimsical and unabashed fun, for creativity, for a positive return on the strangest proof of concept they’ve had in ages. “You just can’t let that kind of momentum go unchecked,” Kranz says.

Perhaps a Trader Joe’s vs. Aldi rave is the happy accident we need right now. A reminder that sometimes, April fools like us just need to give in, don a Hawaiian shirt, and bust out the shopping cart.