Crocs is suing nearly two dozen companies, including Walmart and Hobby Lobby, alleging they copied the “iconic design” of its ubiquitous clogs.

In four lawsuits filed last week, the Colorado-based manufacturer claims the knockoffs infringe on its trademark for the distinctively clunky $50 shoes made with buoyant foam and ventilation holes that can be adorned with charms.

“These actions underscore our determination to take forceful steps to protect our trademarks and other intellectual property,” the company’s chief legal officer, Daniel Hart, said in a statement. “It is essential that we protect Crocs’ iconic DNA, and we will not tolerate the infringement of our rights or those who try to freeride on the investments we have made in our brand.”

The litigation builds on a federal complaint Crocs filed in June seeking to block the import and sale of copycat products. The U.S. International Trade Commission last week said it would look into Crocs’s allegations of trademark infringement against more than 20 companies, including sneaker giant Skechers and luxury brand Loeffler Randall.

Representatives for Walmart, Hobby Lobby and Loeffler Randall did not immediately respond to requests for comment. A spokeswoman for Skechers declined to comment, citing the pending litigation.

Crocs, created two decades ago as an easy-to-clean boating shoe, is one of the country’s most recognizable and polarizing pieces of footwear. It enjoyed massive success in the early 2000s before a downward turn during the Great Recession. But in recent years, the shoe has morphed into a pop-culture staple, dominating social media feeds and turning up on the red carpet at the Academy Awards.

The company’s sales have soared during the pandemic, nearly doubling to $641 million in the most recent quarter. Crocs expects revenue will grow as much as 65 percent this year, to more than $2 billion.

The company has been fighting copycats for years, though analysts say its efforts have gained urgency in recent months as the brand’s popularity has picked up. The latest lawsuits target high-profile national chains, including the nation’s largest retailer, and seek to send a broader message to other retailers that might be considering creating their own foam clogs, said Neil Saunders, managing director of GlobalData Retail in New York.

“Crocs has seen an explosion in popularity, so the knockoff market is worth quite a lot more than it used to be,” he said. “Imitations are a pretty big business in themselves and have a serious impact that dilutes Crocs’ potential revenue.”

Crocs’s shares have shot up more than 260 percent in the last year, to more than $130 per share. And though many apparel and footwear brands have struggled to attract customers during the pandemic, Crocs has benefited from consumers’ widespread shift to casual and comfortable clothing. It also has succeeded in winning over younger shoppers in their teens and 20s, who favor the brand’s bright colors and personalized charms.

“With this revival, they’ve strengthened their board, completely rotated the executive management team and simplified what they stand for, which is the classic clog,” Erinn Murphy, an analyst at Piper Sandler, told The Washington Post last month. “Some people love them, some hate them, but it’s what they’re known for and they’ve really leaned into it.”

A number of high-profile collaborations with celebrities including Post Malone, Justin Bieber and Diplo have further added to the chain’s appeal. Analysts say Crocs has seemingly done the impossible by turning its oft-mocked shoes into a coveted fashion statement.

Now, as the company looks to double down on that growth, they say Crocs is moving away from national chains to focus on selling directly to consumers through its websites and stores. Crocs’s legal actions, they say, are a way to deter future copycats.

“If you’re withdrawing from wholesale partnerships, the last thing you want is retailers trying to replace those styles with their own imitations,” Saunders said. “It’s become particularly important that Crocs not only takes action, but is seen taking action. It is sending a very clear warning that it will jealously guard its patents and trademarks.”