Starter spins and spins….

Hello! Today we wanted to start a cozy Easter exit, my girlfriend has extra fetched her board, both in full adjustment-I start-the starter rotates and does not stop turning off, kill switch, nothing has used. The thing has already smoked like a main student at the toilet, as if the whole place would burn down immediately-you only notice how long such a battery holds off Naja, then pick out keys, remove side pockets-until one with an excavator to the B In any case, I was already a bit hectic, since the thing was smoking and smelling more and more and surrendered like an amok-running transformer – I finally managed to clamp down the minus cable and the spook was over. OK. Ratlessness. What happened there? Anyway, I was just in the garage again, wanted to disassemble the starter and let the part be on for the test – it was immediately there and ran as if nothing had happened. Please to s relevant clues which phenomenon I have experienced here – I have no idea what was going on. THANK YOU Sunny Burner