A new shape changing staple and instrument for the fixation of structures to include bone tissue and industrial materials. This new staple stores elastic mechanical energy to exert force on fixated structures to enhance their security and in bone affect its healing response. This staple once placed changes shape in response to geometric changes in the materials structure, including healing bone tissue. The staple is advanced over prior staples due to its: 1) method of operation, 2) high strength, 3) method of insertion, 4) compressive force temperature independence, 5) energy storing staple retention and delivery system, 6) compatibility with reusable or single use product configuration, 7) efficient and cost effective manufacturing methods, and 8) reduction in the steps required to place the device. In addition to the staple's industrial application an embodiment for use in the fixation of the musculoskeletal system is shown with staple, cartridge, and extrusion handle.