It sounds like the sort of thing fraternity boys would dare each other to eat: a hot dog wrapped in bacon, stuffed in a puffy roll, then smothered in pinto beans, onions, tomatoes, mustard, jalapeno sauce, cheese, maybe a few crumbled potato chips sprinkled on top.

But taste a Sonoran hot dog, a specialty dog of the American Southwest, and the peculiarity washes away, the odd swirl of colours and flavors forming a fusion of flavour that somehow works. And it becomes clear why people, and not just frat kids, will drive across town during rush hour to get one. Or two.

“The mayonnaise, the beans, the green sauce — if you were to describe it somebody, they’d be like, I’m not putting that in my mouth,” said Mike Lowery, web manager for the University of Arizona athletic department and Sonoran dog enthusiast.

“It’s completely different from what we think of as a hot dog, and you need to get somebody to accept that,” he said. “Once you get past that, they see how good it is.”

The Sonoran hot dog, as the name might suggest, is said to have originated from Sonora, Mexico, just over the border from Arizona. Though the exact place and time is hard to pinpoint, Sonoran dogs were served on the streets of Hermosillo, the capitol, around 40 years ago, and tourists have long grabbed late-night “danger dogs” in border towns like Tijuana.

Whatever the dawn of the dog was, it’s taken a foothold in Tucson.

The desert town sandwiched between the Santa Catalina and Rincon mountains has had Sonoran-style hot dogs for decades, but the locals’ affinity for these delicacies got serious around the early 1990s.

Daniel Contreras, owner of the Tuscon restaurant chain El Guero Canelo, was one of the first proprietors to serve bacon-wrapped dogs smothered in everything from the cupboard.

Now, Arizona’s second-largest city boasts well over 100 vendors, the exact number, like the origination point, is tough to determine, selling Sonoran hot dogs, from mobile carts set up under trees and temporary shelters to full-menu restaurants like El Guero’s and BK Carne Asada and Hot Dogs.

“Basically, there had never been hot dog places, but now there’s a lot of them,” said Arturo Contreras, Daniel’s brother and El Guero’s general manager. “The specific taste is something people here like.”

So what makes Sonoran hot dogs so good?

It starts with the bun.

Unlike traditional hot dogs, Sonoran dogs skip the typical bun, coming instead in a soft, puffy blanket of dough known as a bolillo, a savory Mexican bread. The bolillo is not so much sliced, but almost torn open, the ends left closed so the dog and accompanying garnishments sit atop a boat of dough that is sturdy, yet delicate once it hits the mouth.

“Whenever I take someone there, they’re surprised by the bun because it’s not the standard hot dog bun we’re used to,” Lowery said. “It’s a slightly sweet bun and that’s what makes it a little different than the standard American hot dog.”

Well, that and just about everything else.

Since the early days of bacon wrapping, Sonoran hot dogs have become an almost anything-goes endeavour, with everything from sour cream and avocado to shrimp and chorizo, even pineapple and potato chips thrown on top.

The basics are mostly the same, though, starting with the dog in the middle.

Wrapped like a meaty candy cane, the hot dog is grilled so the bacon fuses to it, making it difficult to tell where one starts and the other stops while forming a memorable mouthful that is the foundation of the Sonoran dog.

After the melding of meat, a healthy portion of pinto beans is dropped on top, followed by — not necessarily in this order — diced tomatoes, onions (grilled, raw, sometimes both), mustard, mayonnaise and either jalapeno sauce or salsa. Ketchup and cheese are always options, too.

When it’s done, the Sonoran hot dog looks like a kindergarten finger-painting project and tastes like nothing you ever experienced.

“It is a weird combination, they’re right, but there is a bit of thrill where you taste it and makes you want to have another,” Contreras said. “When you’re eating the hot dogs, about halfway through you start craving another one.”

The key, though, is trying that first dog.

Most people who hear about Sonoran hot dogs turn up their noses at first; the unlikely combination of ingredients just does not sound right to the mustard-ketchup-relish crowd. But once that first bite goes down, it is a pleasantly overwhelming punch to the taste buds, a wave of flavor pulling in another convert.

“I was tentative a little bit at first,” Lowery said. “I had a friend and asked him to take me somewhere that was authentic Mexican food. He took me to El Guero’s and said you’ve got to try a hot dog and I loved it. You’ve just got to start out by getting it with everything and judge it when you’re done.”