This paper deals with the Polish construction 'isc w soldaty (be drafted); lit. become a 'soldat' (solider)', which is grammatically atypical: it is not clear what the value of its noun constituent's case is. The point of departure for the analysis is Igor Melchuk's paper about the parallel Russian construction. (The Polish construction was borrowed from Russian during the Russian rule on Polish territory.) The solution is similar to that for Russian: 'soldaty' in this expression is an atypical (non-virile or depreciative) accusative form. Additionally, some similar expressions consisting of a preposition and a noun form analogous to 'soldaty' are discussed. It is possible to see in them a trace of a new case in Polish (post-prepositional Accusative).