Abstract: An improved animal trap in the shape of an expandable, collapsible, prismoidal box is made of cardboard and has a stiff square top and bottom and four side walls which are foldable to the outside along central folding lines by pressure onto the top. Each side wall has an inwardly extending tongue and at least two tongues on opposite side walls are connected by elastic bands or cntracting springs which pull the walls back from their folded position into a partially planar state as soon as the pressure on the top is released. The square tops are connected by a baited string which hold the trap in its partial planar state thus creating corner openings through which an animal may gain access to the trap interior and baited string. When the baited string is eaten, the contracting spring or rubber band pulls the walls to a fully planar position which now forms a closed prismoidal box thus trapping the animal inside.