In early 2018, Card & Party Giant, a discount party supply store in the Chicago suburbs, discovered Amazon had banned it from selling a popular brand of Halloween costumes. It believed Amazon had done this allegedly at the behest of Rubie's Costume—the self-proclaimed "world's largest costume manufacturer and supplier."

Things quickly escalated. Card & Party is now suing Rubie's Costumes for violating antitrust laws. The complaint alleges that "in an effort to curb competition," Rubie's "has misused Amazon's Branding Registry…as a way to exclude Card & Party from access to Amazon." (Rubie's also sells its costumes directly on Amazon.) And crucially, Rubie's holds exclusive manufacturing licenses over Barbie, Superman, Batman, and Star Wars costumes.