Definition - What does Mousetrap mean?
A Mousetrap is a catching tool which consists of a movable slip that helps to make a variable catch. The tool contains of an open cage which is adapted to fit and slip down in the well tubing. The tool does not release and thus has limited applications. The most common use of the tool is to trap is to catch the sucker rods in a well. The tool has a top, barrel and bottom piece that are all thread together. A larger Mousetrap is used to catch corkscrewed rods in the tubular and casing fish with inconsistent diameters like the corroded or mashed pipes.
Petropedia explains Mousetrap
The Mousetrap consists of a top, barrel and bottom piece, which are all thread together. The extender sections, one or more, are added to the tool by unthreading the top piece from the barrel and the bottom piece and threading the extender sections between them to lengthen the barrel piece and thus increase the functionality of the tool. The bottom piece holds a metal slip that is movable within the grooves milled into the body. The lower end of the side opening in the barrel piece is leveled with an upper shoulder of a slip when it is at the lowest position. Prior-art fishing equipment can replace the top piece of the tool and the bottom piece can be replaced with mill shoe, lip guide, bell or other tools.