Cartoons illustrating the vortex motion that occurs when outflows in the streamer interact with the twisted prominence. The magnetic structures depicted from the bottom to the top include the PIL indicated by the yellow line, multiple bridge-pier-like prominences represented by the blue curves, overlying arcades shown in red, and the streamer shaded in pink and yellow. The straight black arrows represent the plasma propagating upward along the open magnetic fields in the streamer. The curved arrows indicate the outflow being obstructed by the prominence, leading to the formation of vortex motion. As the prominence untwists, its mass at the apex is redistributed up toward the red magnetic arcades, as illustrated in the right panel.