A convertible fishing tool is provided for removing an object (fish) from a wellbore. The fishing tool includes an elongated hollow main housing and a plurality of slip blades that are disposed distal to the main housing and move radially between fully retracted positions and fully extended positions. In the fully retracted positions, the fishing tool is in spear configuration and in the fully extended positions, the fishing tool is in an overshot configuration. The fishing tool also includes an actuation system configured to move the plurality of slip blades in a radial direction between the fully retracted positions and the fully extended positions.