Wis. Stat. § 812.20: Action by defendant against garnishee stayed.

Except upon the order of a judge no action shall be commenced by the defendant or the defendant’s assignee against a garnishee upon any garnisheed claim or demand or to recover any property garnisheed, or execution be issued upon a judgment in favor of defendant against such garnishee, until the termination of the garnishment action; and if an action has been commenced or an execution issued it shall be stayed by the court or a judge thereof as to the garnishee upon the garnishee’s application.