We know the Stranger Things 2-sparked revival of that purple brontosaurus hoodie has been a huge hit for the Science Museum of Minnesota.
The museum sold 10,000 of the retro gems (hoodies, t-shirts and crewnecks) the first day they went on sale, bringing in $400,000.
In the two days after, that number ballooned to more than $600,000. That's 18,000 of the "Thunder Lizard" sweaters and shirts, the museum said Thursday afternoon. They're priced anywhere from $15-$40.
All of the proceeds go to directly advance the mission of the Science Museum, which is a nonprofit. The Thunder Lizard apparel sales will help fund education and outreach programs, the museum says.
Just how big a deal is this for the museum?
Well, the museum did just under $1.1 million in sales at its museum shops during the most recent fiscal year for which figures are available.
So $600,000 in revenue from some old sweaters and shirts? That's reaching nearly 60 percent of an entire year's sales in just a few days.
They've even received orders from around the world.
Steve Fegley, manager of the museum's Explore Store, called it a "one-time miracle" in a statement.
Which is to say this is truly one of the ... stranger things the museum's shop has ever seen.
Kim Ramsden, a spokesperson for the Science Museum of Minnesota, said they're not releasing production costs right now because they're fluctuating based on demand.
But they've been "thrilled by this unexpected opportunity, which gives a healthy boost to the education programs we offer that are inspiring curiosity and a lifelong love of science in young people," she said.
The Science Museum of Minnesota says it reaches more than 200,000 students across all of the state's 87 counties every year.