Doppler response revealing the untwisting of the prominence. In Figure 4, cyan arrows highlight blue shifts, indicating mass motions toward us, while black arrows mark red shifts, representing movements away from us. The bundles of blue and red shifts exhibit a twisting pattern, completing at least 2.5 cycles at 03:38 UT (Panel a), and gradually decreasing to as low as 1 cycle by 07:49 (Panel c).