Es un arma exclusiva del escenario Beetle Lair, ahí después de hacer la transición de escenario tipo Injustice, te acercas al Thoraxe y presionas el Botón Select para usarla.
I download the PSP emulator called PPSSPP, then I download the game, after install the emulator, search the game in the emulator and play it. is a little more "complex", but there's a lot of tutorials in RU-vid. Here is one: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Wk7vlysGwUM.html