Fashion "dupes," or less expensive versions of high-end clothing and other accessories, are just about everywhere these days. They're also drawing some businesses into legal battles.

Lululemon alleges that Costco has stolen the intellectual property of its Scuba hoodies and sweatshirts, Define jackets and ABC pants.

Lululemon is accusing Costco of stealing from its "path-breaking" brand by selling dupes of its sweatshirts, jackets and pants.