Mass. Gen. Laws ch. 236, § 20: Momentary seisin

Section 20. If an execution is levied on land of which a person other than the debtor is actually seized, the officer shall deliver to the creditor or to his attorney such momentary seisin and possession thereof as will enable the creditor to maintain an action therefor upon his own seisin; but the officer shall not oust the tenant then in possession.