Wis. Stat. § 815.57: Sheriff’s deed, recovery of purchase price on eviction.

If the purchaser of real estate sold on execution, the purchaser’s heirs or assigns shall be evicted from such real estate, or if in an action for the recovery thereof judgment shall be rendered against the purchaser or the purchaser’s heirs or assigns in consequence of any irregularity in such sale, or of the judgment upon which such execution issued being vacated or reversed, the purchaser or the purchaser’s heirs or assigns may recover of the party for whose benefit such real estate was sold the amount paid on the purchase thereof, with interest.