I drove to Chicago to try out McDonald's little-known CosMc's test location. Dunkin Donuts should be on alert.

There were no cars in the four drive-thru lanes, and maybe one or two customers in the parking area. I had seen images from the grand opening and the days following that showed lines of cars spilling into the nearby parking lot.

The Dallas locations have the option for walk-up, according to CosMc's website. If this test teaches McDonald's nothing else but how to run a more efficient drive-thru, it will be a huge win for the company.

"You get a Dutch Bros kind of feeling here," Chicago real estate investor Ian Jalali previously told Business Insider, referring to the Oregon-based drive-thru coffee chain expanding across the US. "They look to be combining the all-day breakfast demand with the Starbucks caffeine demand and mixing drinks that are more kid-friendly than Starbucks."

I was expecting more coffee-centric options but there was a much bigger selection of sugary drinks and unusual flavor combinations.

While middle-aged dads like myself are probably not the target market for "Berry Hibiscus Sour-Ade" or "Popping Pear Slush," I can definitely picture my school-aged nieces getting excited about this menu. (My kids are still too young for this much caffeine and sugar.)

I actually had to back up and pull closer to the speaker because I wasn't expecting the payment terminal to be right there when I first drove up.

The character — an orange alien with six arms, a blob-like head, and sneaker-wearing feet — first appeared in a commercial called "The Story of CosMc" in 1987.

With four ordering stations, three windows, and a well-orchestrated fulfillment operation, this location seems like it could process an astronomical number of cars during peak hours.

CosMc's has been touted as McDonald's potential challenge to Starbucks, but coffee snobs will probably stick with the Siren. I think the sweet and savory menu poses a bigger threat to Dunkin' Donuts, especially with emerging Gen Alpha customers.

Even if CosMc's never fully launches as a standalone brand, McDonald's can tap into its caffeinated, sugary menu to pose a considerable challenge to chains like Starbucks and Dutch Bros., too.

McDonald's has revealed little so far — and may never say much — about this experiment in what the company estimates is a $100 billion market opportunity.

Still, CEO Chris Kempczinski gave some hints in April's earnings call.

"What we're still seeing is there's a lot of interest in CosMc's that's sort of curiosity-driven and, as a result of that, it's tough to get a sense of sort of what are the true kind of underlying performance expectations," he said.

"What we're looking at for the ultimate success on this business is we've got to have a business that's driving comparable or stronger [return on investment] to a traditional McDonald's," Kempczinski added.

That's a tall order for CosMc's as a standalone brand, but that still leaves a lot of room for McDonald's to take a bigger bite out of that market.