Intensity time series in the AIA 171 Å band (bottom) starting at 11:50 UT, obtained from a boxcar centred on the cool plasma blob (top). The intensity shows a strong peak at the flare peak time, and then it drops very quickly in approximately 5 min. In the inset plot we show that the oscillations in the intensity profile (black) are in antiphase with the loop thread displacement (dashed red line).