By Anica Padilla

LONGMONT, Colo. (CBS) — Crocs is accusing about 20 companies of copying its popular plastic shoes.

Crocs shoes (credit: TIMOTHY A. CLARY/AFP/Getty Images)

Crocs filed four trademark infringement lawsuits last week. It alleges some of the companies, including Walmart and Hobby Lobby, are selling cheap knockoffs of their plastic clogs.

In one lawsuit, the company pointed out that some customers have left online reviews confusing the shoes with Crocs.

The Crocs headquarters is located in Longmont.

Anica Padilla