The North Face has filed a patent infringement suit against a teenager marketing fleeces, T-shirts and shorts under the brand name “The South Butt.”

In its lawsuit, TNF alleges James Winkelmann Jr., Williams Pharmacy and The South Butt LLC infringed on its patent with their parody product.

Winklemann, 18, created The South Butt two years ago and began selling them through Williams Pharmacy, which owns four drug stores in the St. Louis area. The brand features fleeces, T-shirts and other apparel adorned with a square white on red logo that is very similar to TNF's iconic logo. The South Butt uses the tagline “Never Stop Relaxing” in a parody of TNF's “Never Stop Exploring.”

“Unfortunately, and inevitably, The North Face’s success attracts opportunists seeking to pirate its famous trademarks for their inferior knockoffs,” reads the suit, filed in the US District Court for the Eastern District of Missouri. “The three defendants named here are merely the latest in a long line of such opportunists. They are marketing apparel that directly and unabashedly infringes and dilutes The North Face’s famous trademarks and duplicates The North Face’s trade dress in its iconic Denali jacket.”

Brands have historically had difficulty proving a parody product infringes their patents.

 In its lawsuit TNF alleges that the defendants twice tried to obtain a U.S. trademark registration for The South Butt. When TNF opposed the registration, Winkelmann offered to sell the business to TNF for $1 million. Winkelmann has since withdrawn the offer and plans to expand the manufacture and sale of its line nationwide in the spring, the suit alleges. The company is soliciting additional retail locations and campus reps to represent the company on college campuses.

On Tuesday, The South Butt logo on the company's Twitter page had changed from red to blue. The site was filled with posts from fans citing news reports about the lawsuit.