Wis. Stat. § 66.02165

For a 5-year period after incorporation under this subchapter, a newly incorporated city or village may not add or contract to add any remaining town territory of the town from MUNICIPAL LAW 66.021723 which the newly incorporated city or village was created by use of consolidation, a boundary agreement, or annexation other than annexation by unanimous approval under s. 66.0217 (2), except that the city or village and town territory remaining after incorporation may consolidate as permitted under s. 66.0230.