By now perhaps you've heard of The South Butt and young Jimmy Winkelmann.

Winkelmann is the Ladue teen who dreamed up the clothing line as a parody of The North Face, a brand of trendy fleece jackets and T-shirts popular with outdoorsy types and teenagers.

He did this more than two years ago, inspired to create a logo that spoofed what he saw as a senseless status symbol crowding the hallways of his school, Chaminade College Prep.

But hardly anyone knew what he was up to.

That changed, dramatically, after an attorney for The North Face recently fired off a letter to Winkelmann threatening legal action. He was accused of confusing consumers. Ordered to cease and desist. Now.

It was the best thing that ever happened to The South Butt. That letter became the launching pad for a South Butt marketing campaign unleashed earlier this week. It was a carefully coordinated offensive that turned Winkelmann's sarcastic critique of consumer culture into a case of corporate bullying. It was David vs. Goliath. A college freshman with more outside help than you might think fighting against The North Face, part of a multibillion-dollar apparel empire.

Winkelmann, off studying at the University of Missouri-Columbia, has an attorney arguing his cause, sending out news releases and sounding indignant in media interviews. Others now handle the marketing and distribution for Winkelmann by, for example, revamping the product's website just as the public learned of the dispute.

So The South Butt items are flying off shelves — only because of The North Face's actions.

"It blew up overnight," a stunned Winkelmann, 18, said by phone between classes.

At the Ladue Pharmacy on Clayton Road, the only store that stocks the clothing line, a steady stream of customers sought out The South Butt label. The $19.99 shirts and $69.99 fleeces were hard to miss, on a display just inside the front door.

"I saw it on the news. And it's a hoot. I love it. I do," said Jackie Spaunhorst, a Florissant mother of two, who visited during a lunch break with two co-workers. They bought eight The South Butt T-shirts and shorts among them.

As they left, two other customers waited in line with The South Butt shirts.

"It's been crazy," said Rick Williams, owner of Ladue Pharmacy.

Williams played a key role in helping launch The South Butt. He is friends with Winkelmann's father, Jim, who runs a securities company in Clayton. Williams provided a retail outlet for the younger Winkelmann's idea. To Williams, The South Butt is no different than the "Life is Crap" T-shirts — a play on the popular "Life is Good" brand — that his eclectic pharmacy also sells.

After months of toying with the idea, the two Winkelmanns created The South Butt LLC in March 2007. Business was fine, spinning off about $5,000 in profits — money the younger Winkelmann used to pay for college after his father's company took an unexpected hit earlier this year.

In August, The North Face delivered its letter. Attorney Al Watkins, a friend of the elder Winkelmann, took up The South Butt cause.

"I don't think they have any grounds to stand on," Watkins said. "They're just being bullies."

Trademark attorney Annette Heller of Town and Country, who has no connection to the case, said she suspects The South Butt can prevail if its products are seen as a parody rather than just T-shirts trying to ride another company's coattails.

"If they can present it as a good case of parody, they will win," Heller said.

And young Jimmy Winkelmann is ready.

"I want to fight it," he said.